Benzimidazoles and indoles as taro inhibitors

ABSTRACT

Novel compounds of the structural formula I, and the pharmaceutically acceptable salts thereof, are inhibitors of TarO and may be useful in the prevention, treatment and suppression of diseases mediated by TarO, such as bacterial infections, including gram negative bacterial infections and gram positive bacterial infections such as MRSA and MRSE, alone or in combination with a β-lactam antibiotic.

BACKGROUND OF THE INVENTION

Bacterial antibiotic resistance has become one of the most serious threats to modern health care. Cohen, Science 1992, 257: 1051-1055 discloses that infections caused by resistant bacteria frequently result in longer hospital stays, higher mortality and increased cost of treatment. Neu, Science 1992, 257: 1064-1073 discloses that the need for new antibiotics will continue to escalate because bacteria have a remarkable ability to develop resistance to new agents rendering them quickly ineffective. There have been various efforts to elucidate the mechanisms responsible for bacterial resistance, Coulton et al., Progress in Medicinal Chemistry 1994, 31: 297-349 teaches that the widespread use of penicillins and cephalosporins has resulted in the emergence of β-lactamases, a family of bacterial enzymes that catalyze the hydrolysis of the β-lactam ring common to numerous presently used antibiotics. More recently, Dudley, Pharmacotherapy 1995, 15: 9S-14S has disclosed that resistance mediated by β-lactamases is a critical aspect at the core of the development of bacterial antibiotic resistance.

Methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis (MRSE) have dramatically erroded the efficacy of β-lactam antibiotics. MRSA is emerging as a major cause of bloodstream infections in healthy individuals. In the 2013 Center for Disease Control and Prevention (CDC) Threat Level Report MRSA was designated as the second leading cause of mortality by drug-resistant bacterial pathogen in the US.

The most common mechanism of bacterial resistance to β-lactams involves inactivation by β-lactamases, and a successful strategy to overcome inactivation by combining a β-lactam and a β-lacatmase inhibitor has been used clinically for Gram negative infections (Walsh, C. T. (2003) Antibiotics: Actions, Origins, Resistance, ASM Press, Washington, D.C.). However, Gram positive MRSA strains develop resistance through a different mechanism: the acquisition of a β-lactam resistant peptidoglycan transpeptidase (TP) PBP2A (Beck, W. D., et al., J. Bacteriol. 165, 373-378 (1986); Hartman, B. J., and Tomasz, A. J. Bacteriol. 158, 513-516 (1984)).

The cell wall is the target of many widely used antibiotics, including β-lactams and glycopeptides. Wall teichoic acid (WTA) is an anionic glycophosphate polymer found as a major and integral component of most Gram-positive cell walls (Weidenmaier, C. and Peschel, A., Nature, April 2008, Vol. 6, 278-287; Swoboda, J. G. et al, ACS Chem. Biol. 4, 875-83 (2009); Lee, S. H. et al. Chemistry & Biology 18, 1379-89 (2011)). Although non-essential for S. aureus and B. subtilis at least under laboratory conditions, WTA has been shown to play a critical role in enabling Gram positive bacteria to adhere to an infected host cells (Weidenmaier, C. and Peschel, A., Nature, April 2008, Vol. 6, 278-287); In addition, WTA plays key roles in cell growth, division, peptidoglycan synthesis and β-lactam resistance in methicillin resistant Staphylococcus aureus (MRSA) (Sewell, E. W. C., and Brown, E. d., J. Antibiotics (2014) 67, 43-51; Pasquina, L. W., et al., Current Opinion in Microbiology 2013, 16: 531-537).

S. aureus has been known to evade host innate and adaptive immune defense system even though antibodies generated against S. aureus antigens are present in humans (Foster, Timothy J. Nature Review Microbiology 2005, 3, 948-958). Recently, WTA, as part of the S. aureus cell wall, was implicated in preventing epitope recognition and osponization by antibodies in the host (Spiegel, David A. et al. ACS Chemical Biology, Oct. 26, 2015 Just Accepted Manuscript). Therefore, WTA inhibitors can potentially sensitize pathogens to clearance by the host adaptive immune system. This approach can also be potentially useful for patients who have been previously administered S. aureus vaccine for the prevention of MRSA infections.

A recent study has shown that blocking the expression of wall teichoic acids (WTA) by inhibiting TarO, the first enzyme in the wall techoic acid biosyntheis in S. aureus, sensitizes methicillin-resistant S. aureus (MRSA) strains to β-lactams, even though β-lactam resistant transpeptidase is expressed (Campbell, J. Et al., ACS Chemical Biology, Vol. 6, No. 1, pp. 106-116, 2011). The study further showed that WTA expression is required for methicillin resistance to MRSA, and that preventing WTA biosynthesis by blocking TarO sensitizes MRSA strains to β-lactams due to the combined inactivation of the native penicillin binding proteins (PBP) and TarO. Further, the study showed that treatment of a TarO mutant of MW2, a MRSA strain exhibiting moderate resistance to β-lactams, showed an 8-fold increase in sensitivity to β-lactam antibiotics, including methicillin, imipenem, ceftazidime and cephradine, relative to the parent strain.

Finally, it has been suggested that Ticlopidine, an antiplatelet drug, may show low level activity against TarO and is only synergistic with the β-lactam antibiotic, cefuroxime, and restores the efficacy of cefuroxime in a community acquired MRSA strain USA300 (Sewell, E. W. C., and Brown, E. D., J. Antibiotics (2014) 67, 43-51). Based on these findings, the combination of a TarO inhibitor with a β-lactam antibiotic may be useful for treating MRSA infections, particularly in β-lactam resistant MRSA and MRSE strains.

Due to the decrease in efficacy of β-lactam antibiotics, such as dicloxacillin, cefuroxime and cefepime in treating dangerous bacterial pathogens, there is a need for the development of antibiotic combination agents to perserve the efficacy of β-lactams. The compounds of the present invention are novel TarO inhibitors which may be effective, alone or in combination with a β-lactam antibiotic, in preventing and treating bacterial infections. The compounds of the present invention, alone or in combination with a β-lactam antibiotic, may also be effective in enhancing bacterial clearance by the immune system.

Wall teichoic acids and their relevance to antibiotic resistance are disclosed in: Sewell, Edward W. C., and Brown, E. D., Journal of Antibiotics (2014), 67(1), 43-51; Pasquina, Lincoln W.; et al., Current Opinion in Microbiology (2013), 16(5), 531-537; Brown, E. D., et al., ACS Chemical Biology (2013), 8(1), 226-233; Gilmore, M. S., et al., Antimicrobial Agents and Chemotherapy (2011), 55(2), 767-774; and Swoboda, Jonathan G.; et al., ChemBioChem (2010), 11(1), 35-45.

WTA inhibitors are disclosed in Brown, E. D. et al., Bioorganic & Medicinal Chemistry Letters (2014), 24(3), 905-910; Liang, Lianzhu; et al., Chemistry & Biology (Oxford, United Kingdom) (2013), 20(2), 272-284; Walker, S. et al., Bioorganic & Medicinal Chemistry Letters (2010), 20(5), 1767-1770; and WO2013148269.

SUMMARY OF THE INVENTION

The present invention relates to novel compounds of structural formula I:

and pharmaceutically acceptable salts thereof. The compounds of structural formula I, and embodiments thereof, are inhibitors of TarO and may be useful in the prevention, treatment, and suppression of diseases, disorders and conditions mediated by inhibition of TarO, such as bacterial infections. The compounds of the present invention, and pharmaceutically acceptable salts thereof, are also useful in combination with β-lactam antibiotics, such as imipenem and dicloxacillin, for the treatment of bacterial infections, particularly antibiotic resistant bacterial infections such as methicillin-resistant Staphylocuccus aureus (MRSA) infections.

The present invention also relates to pharmaceutical compositions comprising the compounds of the present invention, or pharmaceutically acceptable salts thereof, and a pharmaceutically acceptable carrier. The present invention also relates to methods for the treatment, control or prevention of disorders, diseases, and conditions that may be responsive to inhibition of TarO in a subject in need thereof by administering the compounds of the present invention, or pharmaceutically acceptable salts thereof, and pharmaceutical compositions of the present invention. The present invention also relates to the use of compounds of the present invention, or pharmaceutically acceptable salts thereof, for manufacture of a medicament useful in treating diseases, disorders and conditions that may be responsive to the inhibition of TarO. The present invention is also concerned with treatment of these diseases, disorders and conditions by administering the compounds of the present invention, or pharmaceutically acceptable salts thereof, in combination with a therapeutically effective amount of another agent that may be useful to treat the disease, disorder and condition. The invention is further concerned with processes for preparing the compounds of the present invention, or pharmaceutically acceptable salts thereof.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is concerned with novel compounds of structural Formula I:

or a pharmaceutically acceptable salt thereof; wherein A is selected from the group consisting of:

-   -   (1) phenyl, and     -   (2) heteroaryl;         X is selected from the group consisting of:     -   (1) N, and     -   (2) CH;         R¹ is selected from the group consisting of:     -   (1) hydrogen,     -   (2) —C₁₋₆ alkyl,     -   (3) —C₂₋₆alkenyl, and     -   (4) —C₂₋₆alkynyl,         wherein alkyl, alkenyl and alkynyl are unsubstituted or         substituted with one to five substituents selected from         —C₁₋₆alkyl;         R² is selected from the group consisting of:     -   (1) —C₁₋₆ alkyl,     -   (2) —C₅₋₈cycloalkyl, and     -   (3) —C₃₋₁₀cycloheteroalkyl,         wherein alkyl, cycloalkyl and cycloheteroalkyl are unsubstituted         or substituted with one to five substituents selected from         R^(a),         or R¹ and R² together with the nitrogen atom to which they are         attached form a monocyclic, bicyclic, spirocyclic or bridged         C₃₋₁₀cycloheteroalkyl ring, wherein the cycloheteroalkyl ring is         unsubstituted or substituted with one to five substituents         selected from —C₁₋₆alkyl, —OC₁₋₆alkyl, and oxo;         R³ is selected from the group consisting of:     -   (1) —(CH₂)_(n)—C₃₋₁₀cycloalkyl,     -   (2) —(CH₂)_(n)—C₃₋₆cycloheteroalkyl,     -   (3) —(CH₂)_(n)-aryl,     -   (4) —(CH₂)_(n)-heteroaryl,     -   (5) —(CH₂)_(n)—NR^(h)—C₃₋₁₀cycloalkyl, and     -   (6) —(CH₂)_(n)—NR^(h)—C₃₋₆cycloheteroalkyl,         wherein each CH₂, cycloalkyl, cycloheteroalkyl, aryl and         heteroaryl is unsubstituted or substituted with one to four         substituents selected from R^(b);         R⁴ is selected from the group consisting of:     -   (1) hydrogen,     -   (2) halogen,     -   (3) —C₁₋₆ alkyl,     -   (4) —OC₁₋₆ alkyl,     -   (5) —C₁₋₆alkyl-OH,     -   (6) —C₁₋₆alkyl-O—C₁₋₆alkyl,     -   (7) —CN,     -   (8) —OH,     -   (9) —(CH₂)_(q)—NR^(c)R^(d),     -   (10) —CO₂C₁₋₆alkyl,     -   (11) —C(O)NR^(c)R^(d),     -   (12) —(CH₂)_(r)—C₃₋₆cycloalkyl,     -   (13) —(CH₂)_(s)—C₂₋₅cycloheteroalkyl,     -   (14) —(CH₂)_(r)-aryl, and     -   (15) —(CH₂)_(r)-heteroaryl,         wherein each CH₂, alkyl, cycloalkyl, cycloheteroalkyl, aryl and         heteroaryl is unsubstituted or substituted with 1-3 substituents         selected from R^(f);         R⁵ is selected from the group consisting of:     -   (1) hydrogen,     -   (2) halogen,     -   (3) —C₁₋₆ alkyl,     -   (4) —OC₁₋₆alkyl,     -   (5) —C₁₋₆alkyl-OH,     -   (6) —C₁₋₆alkyl-O—C₁₋₆alkyl,     -   (7) —CN,     -   (8) —CHF₂,     -   (9) —CF₃,     -   (10) —OH,     -   (11) —(CH₂)_(q)—NR^(c)R^(d),     -   (12) —CO₂C₁₋₆alkyl,     -   (13) —C(O)NR^(c)R^(d),     -   (14) —(CH₂)_(r)—C₃₋₆cycloalkyl,     -   (15) —(CH₂)_(s)—C₂₋₅cycloheteroalkyl,     -   (16) —(CH₂)_(r)-aryl, and     -   (17) —(CH₂)_(r)-heteroaryl,         wherein each CH₂, alkyl, cycloalkyl, cycloheteroalkyl, aryl and         heteroaryl is unsubstituted or substituted with 1-3 substituents         selected from R^(g);         each R^(a) is independently selected from the group consisting         of:     -   (1) halogen,     -   (2) —C₁₋₆alkyl, and     -   (3) —OC₁₋₆alkyl,         wherein each alkyl is unsubstituted or substituted with 1-4         substituents selected from: halogen, —C₁₋₆alkyl, and         —OC₁₋₆alkyl;         each R^(b) is independently selected from the group consisting         of:     -   (1) halogen,     -   (2) —C₁₋₆ alkyl,     -   (3) —OC₁₋₆alkyl,     -   (4) —OH,     -   (5) —CN,     -   (6) —CF₃,     -   (7) —CHF₂,     -   (8) —OCF₃,     -   (9) —OCHF₂,     -   (10) —CO₂C₁₋₆alkyl,     -   (11) —CO₂C₃₋₆cycloalkyl,     -   (12) —(CH₂)_(p)—NHCO₂C₁₋₆alkyl,     -   (13) —C₃₋₆cycloalkyl,     -   (14) —C₂₋₆cycloheteroalkyl,     -   (15) —(CH₂)_(n)-aryl, and     -   (16) —(CH₂)_(n)-heteroaryl,         wherein each alkyl, cycloalkyl, cycloheteroalkyl, aryl and         heteroaryl are unsubstituted or substituted with 1-4         substituents selected from: halogen, —C₁₋₆alkyl, —OC₁₋₆alkyl,         and —CO₂C₁₋₆alkyl;         R^(c) and R^(d) are each independently selected from the group         consisting of:     -   (1) hydrogen,     -   (2) C₁₋₆alkyl,     -   (3) C₃₋₆ cycloalkyl,     -   (4) C₃₋₇ cycloheteroalkyl,     -   (5) —(CH₂)_(t)—NR^(e)R^(e),     -   (6) —(CH₂)_(t)—OR^(e), and     -   (7) —(CH₂)_(t)-heteroaryl,         wherein alkyl, cycloalkyl, cycloheteroalkyl, and heteroaryl are         unsubstituted or substituted with 1-4 substituents selected         from: halogen, —C₁₋₆alkyl, —OC₁₋₆alkyl, —OH, —CH₂CF₃, —CF₃ and         —CO₂C₁₋₆alkyl,         or R^(c) and R^(d) together with the nitrogen atom to which they         are attached form a monocyclic or bicyclic C₃₋₁₀cycloheteroalkyl         ring, wherein the cycloheteroalkyl ring is unsubstituted or         substituted with 1-4 substituents selected from: halogen,         —C₁₋₆alkyl, —OC₁₋₆alkyl, —OH, —CH₂CF₃, —CF₃ and —CO₂C₁₋₆alkyl;         each R^(e) is independently selected from the group consisting         of:     -   (1) hydrogen,     -   (2) C₁₋₆alkyl, and     -   (3) C₃₋₆cycloalkyl;         each R^(f) is independently selected from the group consisting         of:     -   (1) halogen,     -   (2) —OH,     -   (3) —C₁₋₆ alkyl,     -   (4) —OC₁₋₆alkyl,     -   (5) —C₁₋₆ alkyl-OH,     -   (6) —NR^(c)R^(d),     -   (7) —C₃₋₆cycloalkyl, and     -   (8) heteroaryl,         wherein each alkyl, cycloalkyl and heteroaryl is unsubstituted         or substituted with one to three substituents selected from         halogen;

each R^(g) is independently selected from the group consisting of:

-   -   (1) halogen,     -   (2) —OH,     -   (3) —C₁₋₆alkyl,     -   (4) —OC₁₋₆alkyl,     -   (5) —C₁₋₆ alkyl-OH,     -   (6) —NR^(c)R^(d),     -   (7) —C₃₋₆cycloalkyl, and     -   (8) heteroaryl,         wherein each alkyl, cycloalkyl and heteroaryl is unsubstituted         or substituted with one to three substituents selected from         halogen;         each R^(h) is independently selected from the group consisting         of:     -   (1) hydrogen, and     -   (2) —C₁₋₆alkyl;         each n is independently 0, 1 or 2;         each p is independently 0, 1 or 2;         each q is independently 0, 1 or 2;         each r is independently 0, 1 or 2;         each s is independently 0, 1 or 2; and         each t is independently 2, 3 or 4.

The invention has numerous embodiments, which are summarized below. The invention includes the compounds as shown, and also includes individual diastereoisomers, enantiomers, and epimers of the compounds, and mixtures of diastereoisomers and/or enantiomers thereof including racemic mixtures.

In one embodiment of the present invention, A is selected from the group consisting of: phenyl, and heteroaryl. In a class of this embodiment of the present invention, A is selected from the group consisting of: phenyl, and pyridine.

In another embodiment of the present invention, A is phenyl.

In another embodiment of the present invention, A is heteroaryl. In a class of this embodiment, A is pyridine.

In another embodiment of the present invention, X is selected from the group consisting of: N, and CH. In a class of this embodiment, X is N. In another class of this embodiment, X is CH.

In another embodiment of the present invention, R¹ is selected from the group consisting of: hydrogen, —C₁₋₆alkyl, —C₂₋₆alkenyl, and —C₂₋₆alkynyl, wherein alkyl, alkenyl and alkynyl are unsubstituted or substituted with one to five substituents selected from —C₁₋₆alkyl.

In another embodiment of the present invention, R¹ is selected from the group consisting of: hydrogen, and —C₁₋₆alkyl, wherein alkyl is unsubstituted or substituted with one to five substituents selected from —C₁₋₆alkyl. In a class of this embodiment, R¹ is selected from the group consisting of: hydrogen, —CH₃, and —CH₂CH₃.

In another embodiment of the present invention, R¹ is —C₁₋₆alkyl, wherein alkyl is unsubstituted or substituted with one to five substituents selected from —C₁₋₆alkyl. In a class of this embodiment, R¹ is selected from the group consisting of: —CH₃, and —CH₂CH₃.

In another embodiment of the present invention, R¹ is hydrogen.

In another embodiment of the present invention, R² is selected from the group consisting of: —C₁₋₆alkyl, —C₅₋₈cycloalkyl, and —C₃₋₁₀cycloheteroalkyl, wherein alkyl, cycloalkyl and cycloheteroalkyl are unsubstituted or substituted with one to five substituents selected from R^(a), or R¹ and R² together with the nitrogen atom to which they are attached form a monocyclic, bicyclic, spirocyclic or bridged C₃₋₁₀cycloheteroalkyl ring, wherein the cycloheteroalkyl ring is unsubstituted or substituted with one to five substituents selected from —C₁₋₆alkyl, —OC₁₋₆alkyl, and oxo. In a class of this embodiment R² is selected from the group consisting of: —C₁₋₆alkyl, —C₅₋₈cycloalkyl, and —C₃₋₁₀cycloheteroalkyl, wherein alkyl, cycloalkyl and cycloheteroalkyl are unsubstituted or substituted with one to five substituents selected from R^(a), or R¹ and R² together with the nitrogen atom to which they are attached form a monocyclic C₃₋₁₀cycloheteroalkyl ring, wherein the cycloheteroalkyl ring is unsubstituted or substituted with one to five substituents selected from —C₁₋₆alkyl, —OC₁₋₆alkyl, and oxo. In another class of this embodiment R² is selected from the group consisting of: —C₁₋₆alkyl, —C₅₋₈cycloalkyl, and —C₃₋₁₀cycloheteroalkyl, wherein alkyl, cycloalkyl and cycloheteroalkyl are unsubstituted or substituted with one to five substituents selected from R^(a).

In another embodiment of the present invention, R² is selected from the group consisting of: —C₁₋₆alkyl, and —C₅₋₈cycloalkyl, wherein alkyl, and cycloalkyl are unsubstituted or substituted with one to five substituents selected from R^(a), or R¹ and R² together with the nitrogen atom to which they are attached form a monocyclic or bicyclic C₃₋₁₀cycloheteroalkyl ring, wherein the cycloheteroalkyl ring is unsubstituted or substituted with one to five substituents selected from —C₁₋₆alkyl. In a class of this embodiment, R² is selected from the group consisting of: —C₁₋₆alkyl, and —C₅₋₈cycloalkyl, wherein alkyl, and cycloalkyl are unsubstituted or substituted with one to five substituents selected from R^(a), or R¹ and R² together with the nitrogen atom to which they are attached form a monocyclic C₃₋₁₀cycloheteroalkyl ring, wherein the cycloheteroalkyl ring is unsubstituted or substituted with one to five substituents selected from —C₁₋₆alkyl. In another class of this embodiment R² is selected from the group consisting of: —C₁₋₆alkyl, and —C₅₋₈cycloalkyl, wherein alkyl, and cycloalkyl are unsubstituted or substituted with one to five substituents selected from R^(a), or R¹ and R² together with the nitrogen atom to which they are attached form a piperidine ring, wherein the piperidine ring is unsubstituted or substituted with one to five substituents selected from —C₁₋₆alkyl. In another class of this embodiment R² is selected from the group consisting of: —C₁₋₆alkyl, and —C₅₋₈cycloalkyl, wherein alkyl, and cycloalkyl are unsubstituted or substituted with one to five substituents selected from R^(a), or R¹ and R² together with the nitrogen atom to which they are attached form a piperidine ring, wherein the piperidine ring is unsubstituted or substituted with one to five substituents selected from —CH₃.

In another embodiment of the present invention, R² is selected from the group consisting of: —C₁₋₆alkyl, and —C₅₋₈cycloalkyl, wherein alkyl, and cycloalkyl are unsubstituted or substituted with one to five substituents selected from R^(a).

In another embodiment of the present invention, R² is —C₁₋₆alkyl, wherein alkyl is unsubstituted or substituted with one to five substituents selected from R^(a), or R¹ and R² together with the nitrogen atom to which they are attached form a monocyclic, bicyclic, spirocyclic or bridged C₃₋₁₀cycloheteroalkyl ring, wherein the cycloheteroalkyl ring is unsubstituted or substituted with one to five substituents selected from —C₁₋₆alkyl, —OC₁₋₆alkyl, and oxo.

In another embodiment of the present invention, R² is —C₁₋₆alkyl, wherein alkyl is unsubstituted or substituted with one to five substituents selected from R^(a), or R¹ and R² together with the nitrogen atom to which they are attached form a monocyclic or bicyclic C₃₋₁₀cycloheteroalkyl ring, wherein the cycloheteroalkyl ring is unsubstituted or substituted with one to five substituents selected from —C₁₋₆alkyl. In a class of this embodiment, R² is —C₁₋₆alkyl, wherein alkyl is unsubstituted or substituted with one to five substituents selected from R^(a), or R¹ and R² together with the nitrogen atom to which they are attached form a monocyclic C₃₋₁₀cycloheteroalkyl ring, wherein the cycloheteroalkyl ring is unsubstituted or substituted with one to five substituents selected from —C₁₋₆alkyl. In another class of this embodiment R² is —C₁₋₆alkyl, wherein alkyl is unsubstituted or substituted with one to five substituents selected from R^(a), or R¹ and R² together with the nitrogen atom to which they are attached form a piperidine ring, wherein the piperidine ring is unsubstituted or substituted with one to five substituents selected from —C₁₋₆alkyl. In another class of this embodiment R² is —C₁₋₆alkyl, wherein alkyl is unsubstituted or substituted with one to five substituents selected from R^(a), or R¹ and R² together with the nitrogen atom to which they are attached form a piperidine ring, wherein the piperidine ring is unsubstituted or substituted with one to five substituents selected from —CH₃.

In another embodiment of the present invention, R² is —C₁₋₆alkyl, wherein alkyl is unsubstituted or substituted with one to five substituents selected from R^(a).

In another embodiment of the present invention, R² is —C₅₋₈cycloalkyl, wherein cycloalkyl is unsubstituted or substituted with one to five substituents selected from R^(a). In a class of this embodiment, R² is selected from the group consisting of: cyclohexane, and bicyclo[2.2.1]heptane, wherein cyclohexane and bicyclo[2.2.1]heptane are unsubstituted or substituted with one to five substituents selected from R^(a).

In a class of this embodiment, R² is cyclohexane, wherein cyclohexane is unsubstituted or substituted with one to five substituents selected from R^(a). In another class of this embodiment, R² is bicyclo[2.2.1]heptane, wherein bicyclo[2.2.1]heptane is unsubstituted or substituted with one to five substituents selected from R^(a).

In another embodiment, R¹ and R² together with the nitrogen atom to which they are attached form a monocyclic, bicyclic, spirocyclic or bridged C₃₋₁₀cycloheteroalkyl ring, wherein the cycloheteroalkyl ring is unsubstituted or substituted with one to five substituents selected from —C₁₋₆alkyl, —OC₁₋₆alkyl, and oxo.

In another embodiment of the present invention, R¹ and R² together with the nitrogen atom to which they are attached form a monocyclic or bicyclic C₃₋₁₀cycloheteroalkyl ring, wherein the cycloheteroalkyl ring is unsubstituted or substituted with one to five substituents selected from —C₁₋₆alkyl.

In another embodiment of the present invention, R¹ and R² together with the nitrogen atom to which they are attached form a piperidine ring, wherein the piperidine ring is unsubstituted or substituted with one to five substituents selected from —C₁₋₆alkyl. In a class of this embodiment, R¹ and R² together with the nitrogen atom to which they are attached form a piperidine ring, wherein the piperidine ring is unsubstituted or substituted with one to five —CH₃ substituents.

In another embodiment of the present invention, R³ is selected from the group consisting of: —(CH₂)_(n)—C₃₋₁₀cycloalkyl, —(CH₂)_(n)—C₃₋₆cycloheteroalkyl, —(CH₂)_(n)-aryl, —(CH₂)_(n)-heteroaryl, —(CH₂)_(n)—NR^(h)—C₃₋₁₀cycloalkyl, and —(CH₂)_(n)—NR^(h)—C₃₋₆cycloheteroalkyl, wherein each CH₂, cycloalkyl, cycloheteroalkyl, aryl and heteroaryl is unsubstituted or substituted with one to four substituents selected from R^(b).

In another embodiment of the present invention, R³ is selected from the group consisting of: —(CH₂)_(n)—C₃₋₁₀cycloalkyl, —(CH₂)_(n)—C₃₋₆cycloheteroalkyl, —(CH₂)_(n)-aryl, —(CH₂)_(n)-heteroaryl, and —(CH₂)_(n)—NR^(h)—C₃₋₁₀cycloalkyl, wherein each CH₂, cycloalkyl, cycloheteroalkyl, aryl and heteroaryl is unsubstituted or substituted with one to four substituents selected from R^(b).

In another embodiment of the present invention, R³ is selected from the group consisting of: —C₃₋₁₀cycloalkyl, —(CH₂)_(n)—C₃₋₆cycloheteroalkyl, aryl, heteroaryl, and —(CH₂)_(n)—NR^(h)—C₃₋₁₀cycloalkyl, wherein each CH₂, cycloalkyl, cycloheteroalkyl, aryl and heteroaryl is unsubstituted or substituted with one to four substituents selected from R^(b).

In another embodiment of the present invention, R³ is selected from the group consisting of: —(CH₂)_(n)—C₃₋₁₀cycloalkyl, —(CH₂)_(n)—C₂₋₆cycloheteroalkyl, —(CH₂)_(n)-aryl, and —(CH₂)_(n)-heteroaryl, wherein each CH₂, cycloalkyl, cycloheteroalkyl, aryl and heteroaryl is unsubstituted or substituted with one to four substituents selected from R^(b).

In another embodiment of the present invention, R³ is selected from the group consisting of: C₃₋₁₀cycloalkyl, —(CH₂)_(n)—C₂₋₆cycloheteroalkyl, aryl, and heteroaryl, wherein each CH₂, cycloalkyl, cycloheteroalkyl, aryl and heteroaryl is unsubstituted or substituted with one to four substituents selected from R^(b). In a class of this embodiment, R³ is selected from the group consisting of: cyclohexane, pyrrolidine, piperidine, —CH₂-piperidine, phenyl, and pyridine, wherein each CH₂, cyclohexane, pyrrolidine, piperidine, phenyl and pyridine is unsubstituted or substituted with one to four substituents selected from R^(b).

In another embodiment of the present invention, R³ is selected from the group consisting of: C₃₋₁₀cycloalkyl, and —(CH₂)_(n)—C₂₋₆cycloheteroalkyl, wherein each CH₂, cycloalkyl, and cycloheteroalkyl is unsubstituted or substituted with one to four substituents selected from R^(b). In a class of this embodiment of the present invention, R³ is selected from the group consisting of: cyclohexane, -pyrrolidine, piperidine, and —CH₂-piperidine, wherein each cyclohexane, pyrrolidine, piperidine and —CH₂-piperidine is unsubstituted or substituted with one to four substituents selected from R^(b).

In another embodiment of the present invention, R³ is selected from the group consisting of: —C₃₋₁₀cycloalkyl, and —C₂₋₆cycloheteroalkyl, wherein each cycloalkyl and cycloheteroalkyl is unsubstituted or substituted with one to four substituents selected from R^(b). In a class of this embodiment, R³ is selected from the group consisting of: cyclohexane and piperidine, wherein each cyclohexane and piperidine is unsubstituted or substituted with one to four substituents selected from R^(b).

In another embodiment of the present invention, R⁴ is selected from the group consisting of: hydrogen, halogen, —C₁₋₆alkyl, —OC₁₋₆alkyl, —C₁₋₆alkyl-OH, —C₁₋₆alkyl-O—C₁₋₆alkyl, —CN, —OH, —(CH₂)_(q)—NR^(c)R^(d), —CO₂C₁₋₆alkyl, —C(O)NR^(c)R^(d), —(CH₂)_(r)—C₃₋₆cycloalkyl, —(CH₂)_(s)—C₂₋₅cycloheteroalkyl, —(CH₂)_(r)-aryl, and —(CH₂)_(r)-heteroaryl, wherein each CH₂, alkyl, cycloalkyl, cycloheteroalkyl, aryl and heteroaryl is unsubstituted or substituted with 1-3 substituents selected from R^(f).

In another embodiment of the present invention, R⁴ is selected from the group consisting of: hydrogen, halogen, —C₁₋₆alkyl, —OC₁₋₆alkyl, —C₁₋₆alkyl-OH, —CN, —CHF₂, —CF₃, —(CH₂)_(q)—NR^(c)R^(d), —C₃₋₆cycloalkyl, —(CH₂)_(s)—C₂₋₅cycloheteroalkyl, aryl, and heteroaryl, wherein each CH₂, alkyl, cycloalkyl, cycloheteroalkyl, aryl and heteroaryl is unsubstituted or substituted with 1-3 substituents selected from R^(f). In a class of this embodiment, R⁴ is selected from the group consisting of: hydrogen, Br, F, —CH₃, —OCH₃, —CH₂OH, —CN, —CHF₂, —CF₃, —CH₂NH₂, cyclopropyl, —CH₂-azetidine, morpholine, —CH₂-piperazine, CH₂-tetrahydrofuran, phenyl, and pyrazole, wherein each CH₂, cyclopropyl, azetidine, morpholine, piperazine, tetrahydrofuran, phenyl and pyrazole is unsubstituted or substituted with 1-3 substituents selected from R^(f).

In another embodiment of the present invention, R⁴ is selected from the group consisting of: hydrogen, halogen, —C₁₋₆alkyl-OH, —CN, —(CH₂)_(q)—NR^(c)R^(d), —C₃₋₆cycloalkyl, —(CH₂)_(s)—C₂₋₅cycloheteroalkyl, aryl, and heteroaryl, wherein each CH₂, alkyl, cycloalkyl, cycloheteroalkyl, aryl and heteroaryl is unsubstituted or substituted with 1-3 substituents selected from R^(f). In a class of this embodiment, R⁴ is selected from the group consisting of: hydrogen, Br, F, —CH₂OH, —CN, —CH₂NH₂, cyclopropyl, —CH₂-azetidine, morpholine, —CH₂-piperazine, CH₂-tetrahydrofuran, phenyl, and pyrazole, wherein each CH₂, cyclopropyl, azetidine, morpholine, piperazine, tetrahydrofuran, phenyl and pyrazole is unsubstituted or substituted with 1-3 substituents selected from R^(f). In another class of this embodiment, R⁴ is selected from the group consisting of: hydrogen, Br, —CH₂OH, —CN, —CH₂NH₂, cyclopropyl, —CH₂-tetrahydrofuran, phenyl, and pyrazole, wherein each CH₂, cyclopropyl, tetrahydrofuran, phenyl and pyrazole is unsubstituted or substituted with 1-3 substituents selected from R.

In another embodiment of the present invention, R⁴ is selected from the group consisting of: hydrogen, halogen, and —C₁₋₆alkyl, wherein each alkyl is unsubstituted or substituted with 1-3 substituents selected from R^(f).

In another embodiment of the present invention, R⁴ is selected from the group consisting of: hydrogen, and —C₁₋₆alkyl, wherein each alkyl is unsubstituted or substituted with 1-3 substituents selected from R^(f).

In another embodiment of the present invention, R⁴ is —C₁₋₆alkyl, wherein each alkyl is unsubstituted or substituted with 1-3 substituents selected from R^(f).

In another embodiment of the present invention, R⁴ is hydrogen.

In another embodiment of the present invention, R⁵ is selected from the group consisting of: hydrogen, halogen, —C₁₋₆alkyl, —OC₁₋₆alkyl, —C₁₋₆alkyl-OH, —C₁₋₆alkyl-O—C₁₋₆alkyl, —CN, —CHF₂, —CF₃, —OH, —(CH₂)_(q)—NR^(c)R^(d), —CO₂C₁₋₆alkyl, —C(O)NR^(c)R^(d), —(CH₂)_(r)—C₃₋₆cycloalkyl, —(CH₂)_(s)—C₂₋₅cycloheteroalkyl, —(CH₂)_(r)-aryl, and —(CH₂)_(r)-heteroaryl, wherein each CH₂, alkyl, cycloalkyl, cycloheteroalkyl, aryl and heteroaryl is unsubstituted or substituted with 1-3 substituents selected from R^(g).

In another embodiment of the present invention, R⁵ is selected from the group consisting of: hydrogen, halogen, —C₁₋₆alkyl, —OC₁₋₆alkyl, —C₁₋₆alkyl-OH, —CN, —CHF₂, —CF₃, —(CH₂)_(q)—NR^(c)R^(d), —C₃₋₆cycloalkyl, —(CH₂)_(s)—C₂₋₅cycloheteroalkyl, aryl, and heteroaryl, wherein each CH₂, alkyl, cycloalkyl, cycloheteroalkyl, aryl and heteroaryl is unsubstituted or substituted with 1-3 substituents selected from R^(g). In a class of this embodiment, R⁵ is selected from the group consisting of: hydrogen, Br, F, —CH₃, —OCH₃, —CH₂OH, —CN, —CHF₂, —CF₃, —CH₂NH₂, cyclopropyl, —CH₂-azetidine, morpholine, —CH₂-piperazine, CH₂-tetrahydrofuran, phenyl, and pyrazole, wherein each CH₂, cyclopropyl, azetidine, morpholine, piperazine, tetrahydrofuran, phenyl and pyrazole is unsubstituted or substituted with 1-3 substituents selected from R^(g).

In another embodiment of the present invention, R⁵ is selected from the group consisting of: hydrogen, halogen, —C₁₋₆alkyl-OH, —CN, —(CH₂)_(q)—NR^(c)R^(d), —C₃₋₆cycloalkyl, —(CH₂)_(s)—C₂-5cycloheteroalkyl, aryl, and heteroaryl, wherein each CH₂, alkyl, cycloalkyl, cycloheteroalkyl, aryl and heteroaryl is unsubstituted or substituted with 1-3 substituents selected from R^(g). In a class of this embodiment, In another embodiment of the present invention, R⁵ is selected from the group consisting of: hydrogen, Br, F, —CH₂OH, —CN, —CH₂NH₂, cyclopropyl, —CH₂-azetidine, morpholine, —CH₂-piperazine, CH₂-tetrahydrofuran, phenyl, and pyrazole, wherein each CH₂, cyclopropyl, azetidine, morpholine, piperazine, tetrahydrofuran, phenyl and pyrazole is unsubstituted or substituted with 1-3 substituents selected from R^(g). In another class of this embodiment, R⁵ is selected from the group consisting of: hydrogen, Br, —CH₂OH, —CN, —CH₂NH2, cyclopropyl, —CH₂-tetrahydrofuran, phenyl, and pyrazole, wherein each CH₂, cyclopropyl, tetrahydrofuran, phenyl and pyrazole is unsubstituted or substituted with 1-3 substituents selected from R^(g).

In another embodiment of the present invention, R⁵ is selected from the group consisting of: hydrogen, halogen, and —C₁₋₆alkyl, wherein each alkyl is unsubstituted or substituted with 1-3 substituents selected from R^(g). In another embodiment of the present invention, R⁵ is selected from the group consisting of: hydrogen, and —C₁₋₆alkyl, wherein alkyl is unsubstituted or substituted with 1-3 substituents selected from R^(g). In another embodiment of the present invention, R⁵ is —C₁₋₆ alkyl, wherein alkyl is unsubstituted or substituted with 1-3 substituents selected from R^(g).

In another embodiment of the present invention, R⁵ is hydrogen.

In another embodiment of the present invention, each R^(a) is independently selected from the group consisting of: halogen, —C₁₋₆alkyl, and —OC₁₋₆alkyl, wherein alkyl is unsubstituted or substituted with 1-4 substituents selected from: halogen, —C₁₋₆alkyl, and —OC₁₋₆alkyl.

In another embodiment of the present invention, each R^(a) is independently selected from the group consisting of: halogen, and —C₁₋₆alkyl, wherein alkyl is unsubstituted or substituted with 1-4 substituents selected from: halogen, —C₁₋₆alkyl, and —OC₁₋₆alkyl.

In another embodiment of the present invention, R^(a) is —C₁₋₆alkyl, wherein alkyl is unsubstituted or substituted with 1-4 substituents selected from: halogen, —C₁₋₆alkyl, and —OC₁₋₆alkyl. In a class of this embodiment, R^(a) is —C₁₋₆alkyl. In another class of this embodiment, R^(a) is —CH₃.

In another embodiment of the present invention, each R^(b) is independently selected from the group consisting of: halogen, —C₁₋₆alkyl, —OC₁₋₆alkyl, —OH, —CN, —CF₃, —CHF₂, —OCF₃, —OCHF₂, —CO₂C₁₋₆alkyl, —CO₂C₃₋₆cycloalkyl, —(CH₂)_(p)—NHCO₂C₁₋₆alkyl, —C₃₋₆cycloalkyl, —C₂₋₆cycloheteroalkyl, —(CH₂)_(n)-aryl, and —(CH₂)_(n)-heteroaryl, wherein alkyl, cycloalkyl, cycloheteroalkyl, aryl and heteroaryl are unsubstituted or substituted with 1-4 substituents selected from: halogen, —C₁₋₆alkyl, —OC₁₋₆alkyl, and —CO₂C₁₋₆alkyl.

In another embodiment of the present invention, each R^(b) is independently selected from the group consisting of: halogen, —C₁₋₆alkyl, —OC₁₋₆alkyl, —OH, —CN, —CF₃, —CHF₂, —CO₂C₁₋₆alkyl, —CO₂C₃₋₆cycloalkyl, —(CH₂)_(p)—NHCO₂C₁₋₆alkyl, —C₃₋₆cycloalkyl, —C₂₋₆cycloheteroalkyl, aryl, and heteroaryl, wherein alkyl, cycloalkyl, cycloheteroalkyl, aryl and heteroaryl are unsubstituted or substituted with 1-4 substituents selected from: halogen, —C₁₋₆alkyl, —OC₁₋₆alkyl, and —CO₂C₁₋₆alkyl.

In another embodiment of the present invention, each R^(b) is independently selected from the group consisting of: halogen, —C₁₋₆alkyl, —OC₁₋₆alkyl, —CHF₂, —CO₂C₁₋₆alkyl, —(CH₂)_(p)—NHCO₂C₁₋₆alkyl, and heteroaryl, wherein alkyl, and heteroaryl are unsubstituted or substituted with 1-4 substituents selected from: halogen, —C₁₋₆alkyl, and —OC₁₋₆alkyl. In a class of this embodiment, each R^(b) is independently selected from the group consisting of: F, —CH₃, —CH₂CH₃, —C(CH₃)₃, —OCH₂CH₃, —OCH₂CF₃, —CHF₂, —CO₂CH₃, —CO₂CH₂CH₃, —CO₂(CH₂)₂CH₃, —CO₂(CH₂)₃CH₃, —CO₂CH(CH₃)₂, —CO₂C(CH₃)₃, —NHCO₂C(CH₃)₃, —CH₂NHCO₂C(CH₃)₃, pyridine, thiadiazole, pyrimidine, and triazole, wherein alkyl, pyridine, thiadiazole, pyrimidine and triazole are unsubstituted or substituted with 1-4 substituents selected from: halogen, —C₁₋₆alkyl, and —OC₁₋₆alkyl. In another class of this embodiment, each R^(b) is independently selected from the group consisting of: F, —CH₃, —CH₂CH₃, —C(CH₃)₃, —OCH₂CH₃, —OCH₂CF₃, —CHF₂, —CO₂CH₃, —CO₂CH₂CH₃, —CO₂(CH₂)₂CH₃, —CO₂(CH₂)₃CH₃, —CO₂CH(CH₃)₂, —CO₂C(CH₃)₃, —NHCO₂C(CH₃)₃, —CH₂NHCO₂C(CH₃)₃, pyridine, thiadiazole, pyrimidine, and triazole, wherein alkyl, pyridine, thiadiazole, pyrimidine and triazole are unsubstituted or substituted with 1-4 substituents selected from: F, —CH₃, —CH₂CH₃, and —OCH₃.

In another embodiment of the present invention, each R^(b) is independently selected from the group consisting of: halogen, —C₁₋₆alkyl, —CHF₂, —CO₂C₁₋₆alkyl, —(CH₂)_(p)—NHCO₂C₁₋₆alkyl, and heteroaryl, wherein alkyl, and heteroaryl are unsubstituted or substituted with 1-4 substituents selected from: halogen, —C₁₋₆alkyl, and —OC₁₋₆alkyl. In a class of this embodiment, each R^(b) is independently selected from the group consisting of: F, —CH₃, —CH₂CH₃, —C(CH₃)₃, —CHF₂, —CO₂CH₃, —CO₂CH₂CH₃, —CO₂(CH₂)₂CH₃, —CO₂(CH₂)₃CH₃, —CO₂CH(CH₃)₂, —CO₂C(CH₃)₃, —NHCO₂C(CH₃)₃, —CH₂NHCO₂C(CH₃)₃, pyridine, thiadiazole, pyrimidine, and triazole, wherein alkyl, pyridine, thiadiazole, pyrimidine and triazole are unsubstituted or substituted with 1-4 substituents selected from: F, —CH₃, —CH₂CH₃, and —OCH₃. In another class of this embodiment, each R^(b) is independently selected from the group consisting of: F, —CH₃, —CH₂CH₃, —C(CH₃)₃, —CHF₂, —CO₂(CH₂)₃CH₃, —NHCO₂C(CH₃)₃, pyridine, thiadiazole, and pyrimidine, wherein alkyl, pyridine, thiadiazole and pyrimidine are unsubstituted or substituted with 1-4 substituents selected from: —CH₂CH₃, and —OCH₃.

In another embodiment of the present invention, R^(c) and R^(d) are each independently selected from the group consisting of: hydrogen, C₁₋₆alkyl, C₃₋₆cycloalkyl, C₃₋₇cycloheteroalkyl, —(CH₂)_(t)—NR^(e)R^(e), —(CH₂)_(t)—OR^(e), and —(CH₂)_(t)-heteroaryl, wherein alkyl, cycloalkyl, cycloheteroalkyl, and heteroaryl are unsubstituted or substituted with 1-4 substituents selected from: halogen, —C₁₋₆alkyl, —OC₁₋₆alkyl, —OH, —CH₂CF₃, —CF₃ and —CO₂C₁₋₆alkyl, or R^(c) and R^(d) together with the nitrogen atom to which they are attached form a monocyclic or bicyclic C₃₋₁₀cycloheteroalkyl ring, wherein the cycloheteroalkyl ring is unsubstituted or substituted with 1-4 substituents selected from: halogen, —C₁₋₆alkyl, —OC₁₋₆alkyl, —OH, —CH₂CF₃, —CF₃ and —CO₂C₁₋₆alkyl.

In another embodiment of the present invention, R^(c) and R^(d) are each independently selected from the group consisting of: hydrogen, C₁₋₆alkyl, C₃₋₆cycloalkyl, C₃₋₇cycloheteroalkyl, —(CH₂)_(t)—NR^(e)R^(e), —(CH₂)_(t)—OR^(e), and —(CH₂)_(t)-heteroaryl, wherein alkyl, cycloalkyl, cycloheteroalkyl, and heteroaryl are unsubstituted or substituted with 1-4 substituents selected from: halogen, —C₁₋₆alkyl, —OC₁₋₆alkyl, —OH, —CH₂CF₃, —CF₃ and —CO₂C₁₋₆alkyl.

In another embodiment of the present invention, R^(c) and R^(d) are each independently selected from the group consisting of: hydrogen, C₁₋₆alkyl, C₃₋₆cycloalkyl, and C₃₋₇cycloheteroalkyl, wherein alkyl, cycloalkyl and cycloheteroalkyl are unsubstituted or substituted with 1-4 substituents selected from: halogen, —C₁₋₆alkyl, —OC₁₋₆alkyl, —OH, —CH₂CF₃, —CF₃ and —CO₂C₁₋₆alkyl.

In another embodiment of the present invention, R^(c) and R^(d) are each independently selected from the group consisting of: hydrogen, C₁₋₆alkyl, and C₃₋₆cycloalkyl, wherein alkyl and cycloalkyl are unsubstituted or substituted with 1-4 substituents selected from: halogen, —C₁₋₆alkyl, —OC₁₋₆alkyl, —OH, —CH₂CF₃, —CF₃ and —CO₂C₁₋₆alkyl. In another embodiment of the present invention, R^(c) and R^(d) are each independently selected from the group consisting of: hydrogen, —C₁₋₆alkyl, and —C₃₋₆cycloalkyl.

In another embodiment of the present invention, R^(c) and R^(d) are each independently selected from the group consisting of: hydrogen and C₁₋₆alkyl, wherein alkyl is unsubstituted or substituted with 1-4 substituents selected from: halogen, —C₁₋₆alkyl, —OC₁₋₆alkyl, —OH, —CH₂CF₃ and —CF₃. In another embodiment of the present invention, R^(c) and R^(d) are each independently selected from the group consisting of: hydrogen, and —C₁₋₆alkyl. In another embodiment of the present invention, R^(c) and R^(d) are each —C₁₋₆alkyl. In another embodiment of the present invention, R^(c) and R^(d) are each hydrogen.

In another embodiment of the present invention, each R^(c) is independently selected from the group consisting of: hydrogen, —C₁₋₆alkyl, and —C₃₋₆cycloalkyl. In another embodiment of the present invention, each R^(c) is independently selected from the group consisting of: hydrogen, and —C₁₋₆alkyl. In another embodiment of the present invention, R^(c) is —C₁₋₆alkyl. In another embodiment of the present invention, R^(c) is hydrogen.

In another embodiment of the present invention, each R^(d) is independently selected from the group consisting of: hydrogen, —C₁₋₆alkyl, and —C₃₋₆cycloalkyl. In another embodiment of the present invention, each R^(d) is independently selected from the group consisting of: hydrogen, and —C₁₋₆alkyl. In another embodiment of the present invention, R^(d) is —C₁₋₆alkyl. In another embodiment of the present invention, R^(d) is hydrogen.

In another embodiment of the present invention, each R^(e) is independently selected from the group consisting of: hydrogen, —C₁₋₆alkyl, and —C₃₋₆cycloalkyl. In another embodiment of the present invention, each R^(e) is independently selected from the group consisting of: hydrogen, and —C₁₋₆alkyl. In another embodiment of the present invention, R^(e) is —C₁₋₆alkyl. In another embodiment of the present invention, R^(e) is hydrogen.

In another embodiment of the present invention, each R^(f) is independently selected from the group consisting of: halogen, —OH, —C₁₋₆alkyl, —OC₁₋₆alkyl, —C₁₋₆alkyl-OH, —NR^(c)R^(d), —C₃₋₆cycloalkyl, and heteroaryl, wherein each alkyl, cycloalkyl and heteroaryl is unsubstituted or substituted with one to three substituents selected from halogen. In another embodiment of the present invention, each R^(f) is independently selected from the group consisting of: halogen, —C₁₋₆alkyl, —OC₁₋₆ alkyl, —C₁₋₆ alkyl-OH, —NR^(c)R^(d), —C₃₋₆cycloalkyl, and heteroaryl, wherein each alkyl, cycloalkyl and heteroaryl is unsubstituted or substituted with one to three substituents selected from halogen.

In another embodiment of the present invention, each R^(f) is independently selected from the group consisting of: halogen, and —C₁₋₆alkyl, wherein each alkyl is unsubstituted or substituted with one to three substituents selected from halogen. In a class of this embodiment, each R^(f) is independently selected from the group consisting of: F, —CH₃, and —CH₂CF₃, wherein each alkyl is unsubstituted or substituted with one to three F substituents.

In another embodiment of the present invention, R^(f) is —C₁₋₆alkyl, wherein each alkyl is unsubstituted or substituted with one to three F substituents. In a class of this embodiment, R^(f) is —CH₃, wherein —CH₃ is unsubstituted or substituted with one to three substituents selected from F. In a class of this embodiment, R^(f) is —CH₃.

In another embodiment of the present invention, each R^(g) is independently selected from the group consisting of: halogen, —OH, —C₁₋₆alkyl, —OC₁₋₆alkyl, —C₁₋₆alkyl-OH, —NR^(c)R^(d), —C₃₋₆cycloalkyl, and heteroaryl, wherein each alkyl, cycloalkyl and heteroaryl is unsubstituted or substituted with one to three substituents selected from halogen. In another embodiment of the present invention, each R^(g) is independently selected from the group consisting of: halogen, —C₁₋₆alkyl, —OC₁₋₆ alkyl, —C₁₋₆alkyl-OH, —NR^(c)R^(d), —C₃₋₆cycloalkyl, and heteroaryl, wherein each alkyl, cycloalkyl and heteroaryl is unsubstituted or substituted with one to three substituents selected from halogen.

In another embodiment of the present invention, each R^(g) is independently selected from the group consisting of: halogen, and —C₁₋₆alkyl, wherein each alkyl is unsubstituted or substituted with one to three substituents selected from halogen. In a class of this embodiment, each R^(g) is independently selected from the group consisting of: F, —CH₃, and —CH₂CF. In another embodiment of the present invention, R^(g) is —C₁₋₆alkyl, wherein each alkyl is unsubstituted or substituted with one to three F substituents. In a class of this embodiment, R^(g) is —CH₃, wherein —CH₃ is unsubstituted or substituted with one to three F substituents. In a class of this embodiment, R^(g) is —CH₃.

In another embodiment of the present invention, each R^(h) is independently selected from the group consisting of: hydrogen, and —C₁₋₆alkyl. In a class of this embodiment, R^(h) is selected from the group consisting of: —C₁₋₆alkyl. In another class of this embodiment, R^(h) is hydrogen.

In another embodiment of the present invention, n is 0, 1 or 2. In a class of this embodiment, n is 0 or 1. In another class of this embodiment, n is 1 or 2. In another class of this embodiment, n is 0 or 2. In another class of this embodiment, n is 0. In another class of this embodiment, n is 1. In another class of this embodiment, n is 2.

In another embodiment of the present invention, p is 0, 1 or 2. In a class of this embodiment, p is 0 or 1. In another class of this embodiment, p is 1 or 2. In another class of this embodiment, p is 0 or 2. In another class of this embodiment, p is 0. In another class of this embodiment, p is 1. In another class of this embodiment, p is 2.

In another embodiment of the present invention, q is 0, 1 or 2. In a class of this embodiment, q is 0 or 1. In another class of this embodiment, q is 1 or 2. In another class of this embodiment, q is 0 or 2. In another class of this embodiment, q is 0. In another class of this embodiment, q is 1. In another class of this embodiment, q is 2.

In another embodiment of the present invention, r is 0, 1 or 2. In a class of this embodiment, r is 0 or 1. In another class of this embodiment, r is 1 or 2. In another class of this embodiment, r is 0 or 2. In another class of this embodiment, r is 0. In another class of this embodiment, r is 1. In another class of this embodiment, r is 2.

In another embodiment of the present invention, s is 0, 1 or 2. In a class of this embodiment, s is 0 or 1. In another class of this embodiment, s is 1 or 2. In another class of this embodiment, s is 0 or 2. In another class of this embodiment, s is 0. In another class of this embodiment, s is 1. In another class of this embodiment, s is 2.

In another embodiment of the present invention, t is 2, 3 or 4. In a class of this embodiment, t is 2 or 3. In another class of this embodiment, t is 3 or 4. In another class of this embodiment, t is 2 or 4. In another class of this embodiment, t is 2. In another class of this embodiment, t is 3. In another class of this embodiment, t is 4.

In another embodiment of the present invention, the invention relates to compounds of structural formula Ia:

or a pharmaceutically acceptable salt thereof.

In another embodiment of the present invention, the invention relates to compounds of structural formula Ib:

or a pharmaceutically acceptable salt thereof.

In another embodiment of the present invention, the invention relates to compounds of structural formula Ic:

or a pharmaceutically acceptable salt thereof.

In another embodiment of the present invention, the invention relates to compounds of structural formula Id:

or a pharmaceutically acceptable salt thereof.

In another embodiment of the present invention, the invention relates to compounds of structural formula Ie:

or a pharmaceutically acceptable salt thereof.

The compound of structural formula I, includes the compounds of structural formulas Ia, Ib, Ic, Id, and Ie, and pharmaceutically acceptable salts, hydrates and solvates thereof.

Another embodiment of the present invention relates to compounds of structural formula I wherein:

A is selected from the group consisting of:

-   -   (1) phenyl, and     -   (2) heteroaryl;

X is N;

R¹ is selected from the group consisting of:

-   -   (1) hydrogen,     -   (2) —C₁₋₆ alkyl,         wherein alkyl is unsubstituted or substituted with one to five         substituents selected from —C₁₋₆alkyl;         R² is selected from the group consisting of:     -   (1) —C₁₋₆alkyl, and     -   (2) —C₅₋₈cycloalkyl,         wherein alkyl and cycloalkyl are unsubstituted or substituted         with one to five substituents selected from R^(a), or R¹ and R²         together with the nitrogen atom to which they are attached form         a monocyclic or bicyclic C₃₋₁₀cycloheteroalkyl ring, wherein the         cycloheteroalkyl ring is unsubstituted or substituted with one         to five substituents selected from —C₁₋₆alkyl;         R³ is selected from the group consisting of:     -   (1) —C₃₋₁₀cycloalkyl,     -   (2) —(CH₂)_(n)—C₂₋₆cycloheteroalkyl,     -   (3) aryl, and     -   (4) heteroaryl,         wherein CH₂, cycloalkyl, cycloheteroalkyl, aryl and heteroaryl         are unsubstituted or substituted with one to four substituents         selected from R^(b);         R⁴ is selected from the group consisting of:     -   (1) hydrogen, and     -   (2) —C₁₋₆alkyl,         wherein alkyl is unsubstituted or substituted with 1-3         substituents selected from R^(f);         R⁵ is selected from the group consisting of:     -   (1) hydrogen,     -   (2) halogen,     -   (3) —C₁₋₆alkyl,     -   (4) —OC₁₋₆alkyl,     -   (5) —C₁₋₆alkyl-OH,     -   (6) —CN,     -   (7) —CHF₂,     -   (8) —CF₃,     -   (9) —(CH₂)_(q)—NR^(c)R^(d),     -   (10) —C₃₋₆cycloalkyl,     -   (11) —(CH₂)_(s)—C₂₋₅cycloheteroalkyl,     -   (12) aryl, and     -   (13) heteroaryl,         wherein each CH₂, alkyl, cycloalkyl, cycloheteroalkyl, aryl and         heteroaryl is unsubstituted or substituted with 1-3 substituents         selected from R^(g);         or a pharmaceutically acceptable salt thereof.

Another embodiment of the present invention relates to compounds of structural formula I wherein:

A is selected from the group consisting of:

-   -   (1) phenyl, and     -   (2) pyridine;

X is N;

R¹ is —C₁₋₆alkyl, wherein alkyl is unsubstituted or substituted with one to five substituents selected from —C₁₋₆alkyl; R² is —C₅₋₈cycloalkyl, wherein cycloalkyl is unsubstituted or substituted with one to five substituents selected from R^(a); R³ is selected from the group consisting of:

-   -   (1) C₃₋₁₀cycloalkyl, and     -   (2) —C₂₋₆cycloheteroalkyl,         wherein cycloalkyl and cycloheteroalkyl are unsubstituted or         substituted with one to four substituents selected from R^(b);         R⁴ is hydrogen;         R⁵ is selected from the group consisting of:     -   (1) hydrogen,     -   (2) halogen,     -   (3) —C₁₋₆ alkyl-OH,     -   (4) —CN,     -   (5) —(CH₂)_(q)—NR^(c)R^(d),     -   (6) —C₃₋₆cycloalkyl,     -   (7) —(CH₂)_(s)—C₂₋₅cycloheteroalkyl,     -   (8) aryl, and     -   (9) heteroaryl,         wherein each CH₂, alkyl, cycloalkyl, cycloheteroalkyl, aryl and         heteroaryl is unsubstituted or substituted with 1-3 substituents         selected from R^(g);         or a pharmaceutically acceptable salt thereof.

Illustrative, but non-limiting, examples of the compounds of the present invention that are useful as inhibitors of TarO are the following compounds:

or pharmaceutically acceptable salts thereof.

Although the specific stereochemistries described above are preferred, other stereoisomers, including diastereoisomers, enantiomers, epimers, and mixtures of these may also have utility in treating TarO mediated diseases.

Synthetic methods for making the compounds are disclosed in the Examples shown below. Where synthetic details are not provided in the examples, the compounds are readily made by a person of ordinary skill in the art of medicinal chemistry or synthetic organic chemistry by applying the synthetic information provided herein. Where a stereochemical center is not defined, the structure represents a mixture of stereoisomers at that center. For such compounds, the individual stereoisomers, including enantiomers, diastereoisomers, and mixtures of these are also compounds of the invention.

Definitions

“Ac” is acetyl, which is CH₃C(═O)—.

“Alkyl” means saturated carbon chains which may be linear or branched or combinations thereof, unless the carbon chain is defined otherwise. Other groups having the prefix “alk”, such as alkoxy and alkanoyl, also may be linear or branched, or combinations thereof, unless the carbon chain is defined otherwise. Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, sec- and tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, and the like.

“Alkenyl” means carbon chains which contain at least one carbon-carbon double bond, and which may be linear or branched, or combinations thereof, unless otherwise defined. Examples of alkenyl include vinyl, allyl, isopropenyl, pentenyl, hexenyl, heptenyl, 1-propenyl, 2-butenyl, 2-methyl-2-butenyl, and the like.

“Alkynyl” means carbon chains which contain at least one carbon-carbon triple bond, and which may be linear or branched, or combinations thereof, unless otherwise defined. Examples of alkynyl include ethynyl, propargyl, 3-methyl-1-pentynyl, 2-heptynyl and the like.

“Cycloalkyl” means a saturated monocyclic, bicyclic, tricyclic, bridged or spirocyclic carbocyclic ring, having a specified number of carbon atoms. The term may also be used to describe a carbocyclic ring fused to an aryl group. Examples of cycloalkyl include cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl, and the like. In one embodiment of the present invention, cycloalkyl is selected from: cyclohexane and norbornane. In another embodiment of the present invention, cycloalkyl is adamantane. In another embodiment of the present invention, cycloalkyl is cyclopropyl. In another embodiment, cycloalkyl is cyclohexane.

“Cycloheteroalkyl” means a saturated or partly unsaturated non-aromatic monocyclic, bicyclic, tricyclic, bridged or spirocyclic carbocyclic ring or ring system containing at least one ring heteroatom selected from N, NH, S (including SO and SO₂) and O. The cycloheteroalkyl ring may be substituted on the ring carbons and/or the ring nitrogen(s). Examples of cycloheteroalkyl include tetrahydrofuran, pyrrolidine, tetrahydrothiophene, azetidine, piperazine, piperidine, morpholine, oxetane and tetrahydropyran. In one embodiment of the present invention, cycloheteroalkyl is selected from: morpholine, pyrrolidine, piperazine and tetrahydrofuran. In another embodiment of the present invention, cycloheteroalkyl is selected from: pyrrolidine and piperidine. In another embodiment, cycloheteroalkyl is piperidine. In another embodiment of the present invention, cycloheteroalkyl is pyrrolidine or piperidine. In another embodiment of the present invention, cycloheteroalkyl is azetidine, morpholine, piperazine, or tetrahydrofuran.

“Aryl” means a monocyclic, bicyclic, tricyclic, bridged or spirocyclic carbocyclic aromatic ring or ring system containing 5-14 carbon atoms, wherein at least one of the rings is aromatic. The term may also be used to describe a ring system in which a cycloalkyl ring and/or a cycloheteroalkyl ring is fused to an aryl group. Examples of aryl include phenyl and naphthyl. In one embodiment of the present invention, aryl is phenyl.

“Heteroaryl” means monocyclic, bicyclic, tricyclic, bridged or spirocyclic ring or ring system containing 5-14 carbon atoms and containing at least one ring heteroatom selected from N, NH, S (including SO and SO₂) and O, wherein at least one of the heteroatom containing rings is aromatic. The term may also be used to describe a ring system in which a cycloalkyl ring and/or a cycloheteroalkyl ring is fused to a heteroaryl group. Examples of heteroaryl include pyrrolyl, isoxazolyl, isothiazolyl, pyrazolyl, pyridyl, oxazolyl, oxadiazolyl, thiadiazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, furanyl, triazinyl, thienyl, pyrimidyl, pyridazinyl, pyrazinyl, benzisoxazolyl, benzoxazolyl, benzothiazolyl, benzimidazolyl, benzofuranyl, benzothiophenyl, quinolyl, indolyl, isoquinolyl, quinazolinyl, dibenzofuranyl, and the like. In one embodiment of the present invention, heteroaryl is selected from: pyridine, thiadiazole, and pyrimidine. In another embodiment of the present invention, heteroaryl is pyridine. In another embodiment of the present invention, heteroaryl is pyrazole. In another embodiment of the present invention, heteroaryl is pyridine. In another embodiment of the present invention, heteroaryl is pyrazole. In another embodiment, heteroaryl is pyridine, thiadiazole, pyrimidine, or triazole.

“Halogen” includes fluorine, chlorine, bromine and iodine.

“Me” represents methyl.

When any variable (e.g., R¹, R^(a), etc.) occurs more than one time in any constituent or in formula I, its definition on each occurrence is independent of its definition at every other occurrence. Also, combinations of substituents and/or variables are permissible only if such combinations result in stable compounds. A squiggly line across a bond in a substituent variable represents the point of attachment.

Under standard nomenclature used throughout this disclosure, the terminal portion of the designated side chain is described first, followed by the adjacent functionality toward the point of attachment. For example, a C₁₋₅ alkylcarbonylamino C₁₋₆ alkyl substituent is equivalent to:

In choosing compounds of the present invention, one of ordinary skill in the art will recognize that the various substituents, i.e. R¹, R², etc., are to be chosen in conformity with well-known principles of chemical structure connectivity and stability.

The term “substituted” shall be deemed to include multiple degrees of substitution by a named substitutent. Where multiple substituent moieties are disclosed or claimed, the substituted compound can be independently substituted by one or more of the disclosed or claimed substituent moieties, singly or plurally. By independently substituted, it is meant that the (two or more) substituents can be the same or different.

The phrase “pharmaceutically acceptable” is employed herein to refer to those compounds, materials, compositions, salts and/or dosage forms which are, using sound medical judgment, and following all applicable government regulations, safe and suitable for administration to a human being or an animal.

The term “% enantiomeric excess” (abbreviated “ee”) shall mean the % major enantiomer less the % minor enantiomer. Thus, a 70% enantiomeric excess corresponds to formation of 85% of one enantiomer and 15% of the other. The term “enantiomeric excess” is synonymous with the term “optical purity.”

Compounds of Formula I may contain one or more asymmetric centers and can thus occur as racemates and racemic mixtures, single enantiomers, diastereomeric mixtures and individual diastereomers. The present invention is meant to encompass all such isomeric forms of the compounds of Formula I.

The independent syntheses of optical isomers and diastereoisomers or their chromatographic separations may be achieved as known in the art by appropriate modification of the methodology disclosed herein. Their absolute stereochemistry may be determined by the X-ray crystallography of crystalline products or crystalline intermediates which are derivatized, if necessary, with a reagent containing an asymmetric center of known absolute configuration.

If desired, racemic mixtures of the compounds may be separated so that the individual enantiomers are isolated. The separation can be carried out by methods well-known in the art, such as the coupling of a racemic mixture of compounds to an enantiomerically pure compound to form a diastereoisomeric mixture, followed by separation of the individual diastereoisomers by standard methods, such as fractional crystallization or chromatography. The coupling reaction is often the formation of salts using an enantiomerically pure acid or base. The diasteromeric derivatives may then be converted to the pure enantiomers by cleavage of the added chiral residue. The racemic mixture of the compounds can also be separated directly by chromatographic methods utilizing chiral stationary phases, which methods are well known in the art.

Alternatively, any enantiomer of a compound may be obtained by stereoselective synthesis using optically pure starting materials or reagents of known configuration by methods well known in the art.

Some of the compounds described herein contain olefinic double bonds, and unless specified otherwise, are meant to include both E and Z geometric isomers.

Tautomers are defined as compounds that undergo rapid proton shifts from one atom of the compound to another atom of the compound. Some of the compounds described herein may exist as tautomers with different points of attachment of hydrogen. Such an example may be a ketone and its enol form known as keto-enol tautomers. The individual tautomers as well as mixture thereof are encompassed with compounds of Formula I.

In the compounds of general formula I, the atoms may exhibit their natural isotopic abundances, or one or more of the atoms may be artificially enriched in a particular isotope having the same atomic number, but an atomic mass or mass number different from the atomic mass or mass number predominately found in nature. The present invention is meant to include all suitable isotopic variations of the compounds of structural formula I. For example, different isotopic forms of hydrogen (H) include protium (¹H), deuterium (²H), and tritium (³H). Protium is the predominant hydrogen isotope found in nature. Enriching for deuterium may afford certain therapeutic advantages, such as increasing in vivo half-life or reducing dosage requirements, or may provide a compound useful as a standard for characterization of biological samples. Tritium is radioactive and may therefore provide for a radiolabeled compound, useful as a tracer in metabolic or kinetic studies. Isotopically-enriched compounds within structural formula I, can be prepared without undue experimentation by conventional techniques well known to those skilled in the art or by processes analogous to those described in the Schemes and Examples herein using appropriate isotopically-enriched reagents and/or intermediates.

Furthermore, some of the crystalline forms for compounds of the present invention may exist as polymorphs and as such are intended to be included in the present invention. In addition, some of the compounds of the instant invention may form solvates with water or common organic solvents. Such solvates are encompassed within the scope of this invention.

It is generally preferable to administer compounds of the present invention as enantiomerically pure formulations. Racemic mixtures can be separated into their individual enantiomers by any of a number of conventional methods. These include chiral chromatography, derivatization with a chiral auxiliary followed by separation by chromatography or crystallization, and fractional crystallization of diastereomeric salts.

Salts:

It will be understood that the present invention includes compounds of the present invention and the pharmaceutically acceptable salts thereof. The present invention also includes salts that are not pharmaceutically acceptable when they are used as precursors to the free compounds or their pharmaceutically acceptable salts or in other synthetic manipulations.

The compounds of the present invention may be administered in the form of a pharmaceutically acceptable salt. The term “pharmaceutically acceptable salt” refers to salts prepared from pharmaceutically acceptable non-toxic bases or acids including inorganic or organic bases and inorganic or organic acids. Salts of basic compounds encompassed within the term “pharmaceutically acceptable salt” refer to non-toxic salts of the compounds of this invention which are generally prepared by reacting the free base with a suitable organic or inorganic acid. Representative salts of basic compounds of the present invention include, but are not limited to, the following: acetate, benzenesulfonate, benzoate, bicarbonate, bisulfate, bitartrate, borate, bromide, camsylate, carbonate, chloride, clavulanate, citrate, dihydrochloride, edetate, edisylate, estolate, esylate, fumarate, gluceptate, gluconate, glutamate, glycollylarsanilate, hexylresorcinate, hydrabamine, hydrobromide, hydrochloride, hydroxynaphthoate, iodide, isothionate, lactate, lactobionate, laurate, malate, maleate, mandelate, mesylate, methylbromide, methylnitrate, methylsulfate, mucate, napsylate, nitrate, N-methylglucamine ammonium salt, oleate, oxalate, pamoate (embonate), palmitate, pantothenate, phosphate/diphosphate, polygalacturonate, salicylate, stearate, sulfate, subacetate, succinate, tannate, tartrate, teoclate, tosylate, triethiodide and valerate. Furthermore, where the compounds of the invention carry an acidic moiety, suitable pharmaceutically acceptable salts thereof include, but are not limited to, salts derived from inorganic bases including aluminum, ammonium, calcium, copper, ferric, ferrous, lithium, magnesium, manganic, mangamous, potassium, sodium, zinc, and the like. Particularly preferred are the ammonium, calcium, magnesium, potassium, and sodium salts. Salts derived from pharmaceutically acceptable organic non-toxic bases include salts of primary, secondary, and tertiary amines, cyclic amines, and basic ion-exchange resins, such as arginine, betaine, caffeine, choline, N,N-dibenzylethylenediamine, diethylamine, 2-diethylaminoethanol, 2-dimethylaminoethanol, ethanolamine, ethylenediamine, N-ethylmorpholine, N-ethylpiperidine, glucamine, glucosamine, histidine, hydrabamine, isopropylamine, lysine, methylglucamine, morpholine, piperazine, piperidine, polyamine resins, procaine, purines, theobromine, triethylamine, trimethylamine, tripropylamine, tromethamine, and the like.

Also, in the case of a carboxylic acid (—COOH) or alcohol group being present in the compounds of the present invention, pharmaceutically acceptable esters of carboxylic acid derivatives, such as methyl, ethyl, or pivaloyloxymethyl, or acyl derivatives of alcohols, such as O-acetyl, O-pivaloyl, O-benzoyl, and O-aminoacyl, can be employed. Included are those esters and acyl groups known in the art for modifying the solubility or hydrolysis characteristics for use as sustained-release or prodrug formulations.

Solvates, and in particular, the hydrates of the compounds of the present invention are included in the present invention as well.

Utilities

The compounds of the present invention are TarO inhibitors, and may be useful to treat diseases that are modulated by TarO inhibitors. Many of these diseases are summarized below.

The compounds of the present invention, and pharmaceutically acceptable salts thereof, may be useful for the treatment, prevention or suppression of a bacterial infection, including but not limited to, a gram negative bacterial infection, a gram-positive bacterial infection, a methicillin-resistant S. aureus (MRSA) bacterial infection, and/or a methicillin-resistant S. epidermidis (MRSE) bacterial infection.

The compounds of the present invention, and pharmaceutically acceptable salts thereof, may also be useful to sensitize bacteria to a subject's innate immune response and enhance bacterial clearance by the subject's immune system, including but not limited to gram negative bacteria, gram positive bacteria, MRSA bacteria and MRSE bacteria.

Further, the compounds of the present invention, and pharmaceutically acceptable salts thereof, in combination with a β-lactam antibiotic, may be useful for the treatment, prevention or suppression of a bacterial infection, including but not limited to, a gram-positive bacterial infection, a methicillin-resistant S. aureus (MRSA) bacterial infection, and/or a methicillin-resistant S. epidermidis (MRSE) bacterial infection.

Further, the compounds of the present invention, and pharmaceutically acceptable salts thereof, may also be useful in combination with a β-lactam antibiotic, including but not limited to a penicillin antibiotic, a cephamycin antibiotic, a cephalosporin antibiotic or a carbapenem antibiotic, for the treatment of bacterial infections, particularly antibiotic resistant gram negative and/or gram positive bacterial infections such as MRSA infections and/or MRSE infections.

In particular, the compounds of the present invention, and pharmaceutically acceptable salts thereof, may be useful in combination with imipenem for the treatment of bacterial infections, particularly antibiotic resistant gram negative and/or gram positive bacterial infections such as MRSA infections, and/or MRSE infections.

In particular, the compounds of the present invention, and pharmaceutically acceptable salts thereof, may also be useful in combination with dicloxacillin for the treatment of bacterial infections, particularly antibiotic resistant gram negative and/or gram positive bacterial infections such as MRSA infections and/or MRSE infections.

The compounds of the present invention, or pharmaceutically acceptable salts thereof, alone or in combinations with a β-lactam antibiotic, may be effective in restoring bacterial susceptibility to treatment with a β-lactam antibiotic in a subject, including but not limited to, decreasing gram negative susceptibility, gram positive bacterial susceptibility, methicillin-resistant S. aureus (MRSA) bacterial susceptibility, and/or methicillin-resistant S. epidermidis (MRSE) bacterial susceptibility.

The compounds of the present invention, or pharmaceutically acceptable salts thereof, alone or in combinations with a β-lactam antibiotic, may also be effective in restoring bacterial susceptibility to treatment with a β-lactam antibiotic in a bacterial cell culture, including but not limited to, decreasing gram negative susceptibility, gram positive bacterial susceptibility, methicillin-resistant S. aureus (MRSA) bacterial susceptibility, and/or methicillin-resistant S. epidermidis (MRSE) bacterial susceptibility.

The compounds of the present invention, or pharmaceutically acceptable salts thereof, alone or in combinations with a β-lactam antibiotic, may be effective in decreasing bacterial resistance to treatment with a β-lactam antibiotic in a subject, including but not limited to, decreasing gram negative bacterial resistance, decreasing gram positive bacterial resistance, methicillin-resistant S. aureus (MRSA) bacterial resistance, and/or methicillin-resistant S. epidermidis (MRSE) bacterial resistance.

The compounds of the present invention, or pharmaceutically acceptable salts thereof, alone or in combination with a β-lactam antibiotic may be effective in treating highly resistant infections in a subject, including but not limited to, gram negative bacterial infections, gram positive bacterial infections, methicillin-resistant S. aureus (MRSA) bacterial infections, and/or methicillin-resistant S. epidermidis (MRSE) bacterial infections.

The compounds of the present invention, or pharmaceutically acceptable salts thereof, alone or in combination with a β-lactam antibiotic may be effective in increasing β-lactam antibiotic effectiveness to treat a bacterial infection in a subject, including but not limited to, a gram negative bacterial infection, a gram positive bacterial infection, a methicillin-resistant S. aureus (MRSA) bacterial infection, and/or a methicillin-resistant S. epidermidis (MRSE) bacterial infection.

The compounds of the present invention, or pharmaceutically acceptable salts thereof, in combination with a β-lactam antibiotic may increase bacterial susceptibility to treatment with a β-lactam antibiotic in a subject, wherein the bacteria includes but is not limited to gram negative bacteria, gram positive bacteria, methicillin-resistant S. aureus (MRSA) bacteria, and/or methicillin-resistant S. epidermidis (MRSE) bacteria.

The compounds of the present invention, or pharmaceutically acceptable salts thereof, in combination with a β-lactam antibiotic may provide bactericidal synergy against bacterial infections in a subject, including but not limited to, gram negative bacterial infections, gram positive bacterial infections, methicillin-resistant S. aureus (MRSA) bacterial infections, and/or methicillin-resistant S. epidermidis (MRSE) bacterial infections.

The compounds of this invention, or pharmaceutically acceptable salts thereof, alone or in combination with a β-lactam antibiotic, may also have utility in lowering the bacterial load in a subject. In particular, the compounds of this invention, or pharmaceutically acceptable salts thereof, may have utility in lowering the bacterial level in a subject, alone or in combination with imipenem or dicloxacillin.

The compounds of the present invention may be useful for the treatment or prevention of one or more of the following diseases by administering a therapeutically effective amount or a prophylactically effective amount of the compound of formula I, or a pharmaceutically acceptable salt thereof, to a patient in need of treatment:

-   -   (1) bacterial infections;     -   (2) gram negative bacterial infections;     -   (3) gram positive bacterial infections;     -   (4) methicillin-resistant S. aureus (MRSA) infections; and     -   (5) methicillin-resistant S. epidermidis (MRSE) infections.

One or more of these diseases may be treated by the administration of a therapeutically effective amount of a compound of the present invention, or a pharmaceutically acceptable salt thereof, to a patient in need of treatment. Further, one or more of these diseases may be prevented by the administration of a prophylactically effective amount of a compound of the present invention, or a pharmaceutically acceptable salt thereof, to a patient in need of treatment.

The compounds of the present invention may be useful for the treatment or prevention of one or more of the following diseases by administering a therapeutically effective or prophylactically effective amount of the compound of formula I, or a pharmaceutically acceptable salt thereof, and a β-lactam antibiotic, including but not limited to a penicillin antibiotic, a cephamycin antibiotic, a cephalosporin antibiotic or a carbapenem antibiotic, to a patient in need of treatment.

-   -   (1) bacterial infections;     -   (2) gram negative bacterial infections;     -   (3) gram positive bacterial infections;     -   (4) methicillin-resistant S. aureus (MRSA) infections; and     -   (5) methicillin-resistant S. epidermidis (MRSE) infections.

One or more of these diseases may be treated by the administration of a therapeutically effective amount of a compound of the present invention, or a pharmaceutically acceptable salt thereof, and a β-lactam antibiotic selected from: a penicillin antibiotic, a cephamycin antibiotic, a cephalosporin antibiotic and a carbapenem antibiotic, to a patient in need of treatment. Further, one or more of these diseases may be prevented by the administration of a prophylactically effective amount of a compound of the present invention, or a pharmaceutically acceptable salt thereof, and a β-lactam antibiotic selected from: a penicillin antibiotic, a cephamycin antibiotic, a cephalosporin antibiotic and a carbapenem antibiotic, to a patient in need of treatment.

In particular, the compounds of the present invention may also be useful for the treatment or prevention of one or more of the following diseases by administering a therapeutically effective amount or prophylactically effective amount of the compound of formula I, or a pharmaceutically acceptable salt thereof, and dicloxacillin to a patient in need of treatment:

-   -   (1) bacterial infections;     -   (2) gram negative bacterial infections;     -   (3) gram positive bacterial infections;     -   (4) methicillin-resistant S. aureus (MRSA) infections; and     -   (5) methicillin-resistant S. epidermidis (MRSE) infections.

One or more of these diseases may be treated by the administration of a therapeutically effective amount of a compound of the present invention, or a pharmaceutically acceptable salt thereof, and dicloxacillin, or a pharmaceutically acceptable salt or prodrug thereof, to a patient in need of treatment. Further, one or more of these diseases may be prevented by the administration of a prophylactically effective amount of a compound of the present invention, or a pharmaceutically acceptable salt thereof, and dicloxacillin, or a pharmaceutically acceptable salt or prodrug thereof, to a patient in need of treatment.

In particular, the compounds of the present invention may also be useful for the treatment or prevention of one or more of the following diseases by administering a therapeutically effective amount or prophylactically effective amount of the compound of formula I, or a pharmaceutically acceptable salt thereof, and imipenem to a patient in need of treatment:

-   -   (1) bacterial infections;     -   (2) gram negative bacterial infections;     -   (3) gram positive bacterial infections;     -   (4) methicillin-resistant S. aureus (MRSA) infections; and     -   (5) methicillin-resistant S. epidermidis (MRSE) infections.

One or more of these diseases may be treated by the administration of a therapeutically effective amount of a compound of the present invention, or a pharmaceutically acceptable salt thereof, and imipenem, or a pharmaceutically acceptable salt or prodrug thereof, to a patient in need of treatment. Further, one or more of these diseases may be prevented by the administration of a prophylactically effective amount of a compound of the present invention, or a pharmaceutically acceptable salt thereof, and imipenem, or a pharmaceutically acceptable salt or prodrug thereof, to a patient in need of treatment.

The compounds of the present invention, alone or in combination with a β-lactam antibiotic, may be useful in the following methods of treatment.

In another embodiment the present invention relates to a method of treating or preventing a disorder, condition or disease that is responsive to the inhibition of TarO in a patient in need thereof comprising administration of a therapeutically effective amount of a compound according to claims 1-16, or a pharmaceutically acceptable salt thereof.

In another embodiment the present invention relates to a method of treating a bacterial infection in a patient in need of treatment comprising the administration to the patient of a therapeutically effective amount of a compound of claims 1-16, or a pharmaceutically acceptable salt thereof. In a class of this embodiment, the bacterial infection is a methicillin-resistant S. aureus infection or a methicillin-resistant S. epidermidis infection.

In another embodiment the present invention relates to a method of treating a bacterial infection in a patient in need of treatment comprising the administration to the patient of a therapeutically effective amount of a compound of claims 1-16, or a pharmaceutically acceptable salt thereof, in combination with a β-lactam antibiotic, or a pharmaceutically acceptable salt thereof. In a class of this embodiment, the bacterial infection is a methicillin-resistant S. aureus infection or a methicillin-resistant S. epidermidis infection. In another class of this embodiment, the β-lactam antibiotic is imipenem or dicloxacillin.

A method of treating a bacterial infection comprising the administration of a therapeutically effective amount of a compound of formula I, or a pharmaceutically acceptable salt thereof, to a patient in need of treatment. In one embodiment, the bacterial infection is a gram positive bacterial infection. In another embodiment, the bacterial infection is a gram negative bacterial infection. In another embodiment, the bacterial infection is a MRSA infection. In another embodiment, the bacterical infection is a MRSE infection.

A method of treating a bacterial infection comprising administration of a therapeutically effective amount of a compound of formula I, or a pharmaceutically acceptable salt thereof, and a therapeutically effective amount of a β-lactam antibiotic, or a pharmaceutically acceptable salt thereof, to a patient in need of treatment. In one embodiment the β-lactam antibiotic is selected from: a penicillin antibiotic, a cephamycin antibiotic, a cephalosporin antibiotic or a carbapenem antibiotic. In another embodiment, the β-lactam antibiotic is selected from: a penicillin antibiotic and a carbapenem antibiotic. In another embodiment, the β-lactam antibiotic is a penicillin antibiotic. In a class of this embodiment, the penicillin antibiotic is dicloxacillin. In another embodiment, the β-lactam antibiotic is a carbapenem antibiotic. In a class of this embodiment, the carbapenem antibiotic is imipenem.

A method of treating a gram negative and/or a gram positive bacterial infection comprising administration of a therapeutically effective amount of a compound of formula I, or a pharmaceutically acceptable salt thereof, and a therapeutically effective amount of a β-lactam antibiotic, or a pharmaceutically acceptable salt thereof, to a patient in need of treatment. In one embodiment the β-lactam antibiotic is selected from: a penicillin antibiotic, a cephamycin antibiotic, a cephalosporin antibiotic or a carbapenem antibiotic. In another embodiment, the β-lactam antibiotic is selected from: a penicillin antibiotic and a carbapenem antibiotic. In another embodiment, the β-lactam antibiotic is a penicillin antibiotic. In a class of this embodiment, the penicillin antibiotic is dicloxacillin. In another class of this embodiment, the bacterial infection is a gram positive bacterial infection and the penicillin antibiotic is dicloxacillin. In another embodiment, the β-lactam antibiotic is a carbapenem antibiotic. In a class of this embodiment, the carbapenem antibiotic is imipenem. In another class of this embodiment, the bacterial infection is a gran negative bacterial infection and a gram positive bacterial infection and the carbapenem antibiotic is imipenem. In another class of this embodiment, the bacterial infection is a gran negative bacterial infection and the carbapenem antibiotic is imipenem. In another class of this embodiment, the bacterial infection is a gram positive bacterial infection and the carbapenem antibiotic is imipenem.

A method of treating MRSA infection comprising administration of a therapeutically effective amount of a compound of formula I, or a pharmaceutically acceptable salt thereof, and a therapeutically effective amount of a β-lactam antibiotic, or a pharmaceutically acceptable salt thereof, to a patient in need of treatment. In one embodiment the β-lactam antibiotic is selected from: a penicillin antibiotic, a cephamycin antibiotic, a cephalosporin antibiotic or a carbapenem antibiotic. In another embodiment, the β-lactam antibiotic is selected from: a penicillin antibiotic and a carbapenem antibiotic. In another embodiment, the β-lactam antibiotic is a penicillin antibiotic. In a class of this embodiment, the penicillin antibiotic is dicloxacillin. In another embodiment, the β-lactam antibiotic is a carbapenem antibiotic. In a class of this embodiment, the carbapenem antibiotic is imipenem.

A method of treating MRSE infection comprising administration of a therapeutically effective amount of a compound of formula I, or a pharmaceutically acceptable salt thereof, and a therapeutically effective amount of a β-lactam antibiotic, or a pharmaceutically acceptable salt thereof, to a patient in need of treatment. In one embodiment the β-lactam antibiotic is selected from: a penicillin antibiotic, a cephamycin antibiotic, a cephalosporin antibiotic or a carbapenem antibiotic. In another embodiment, the β-lactam antibiotic is selected from: a penicillin antibiotic and a carbapenem antibiotic. In another embodiment, the β-lactam antibiotic is a penicillin antibiotic. In a class of this embodiment, the penicillin antibiotic is dicloxacillin. In another embodiment, the β-lactam antibiotic is a carbapenem antibiotic. In a class of this embodiment, the carbapenem antibiotic is imipenem.

A method of treating a bacterial infection by sensitizing the bacteria to the subject's immune system response comprising the administration of a therapeutically effective amount of a compound of formula I, or a pharmaceutically acceptable salt thereof, to a patient in need of treatment. In one embodiment, the bacterial infection is a gram positive bacterial infection. In another embodiment, the bacterial infection is a gram negative bacterial infection. In another embodiment, the bacterial infection is a MRSA infection. In another embodiment, the bacterical infection is a MRSE infection.

A method of preventing a bacterial infection comprising the administration of a prophylactically effective amount of a compound of formula I, or a pharmaceutically acceptable salt thereof, to a patient in need of treatment. In one embodiment, the bacterial infection is a gram positive bacterial infection. In another embodiment, the bacterial infection is a gram negative bacterial infection. In another embodiment, the bacterial infection is a MRSA infection. In another embodiment, the bacterial infection is a MRSE infection.

A method of preventing a bacterial infection comprising administration of a prophylactically effective amount of a compound of formula I, or a pharmaceutically acceptable salt thereof, and a prophylactically effective amount of a β-lactam antibiotic, or a pharmaceutically acceptable salt thereof, to a patient in need of treatment. In one embodiment the β-lactam antibiotic is selected from: a penicillin antibiotic, a cephamycin antibiotic, a cephalosporin antibiotic or a carbapenem antibiotic. In another embodiment, the β-lactam antibiotic is selected from: a penicillin antibiotic and a carbapenem antibiotic. In another embodiment, the β-lactam antibiotic is a penicillin antibiotic. In a class of this embodiment, the penicillin antibiotic is dicloxacillin. In another embodiment, the β-lactam antibiotic is a carbapenem antibiotic. In a class of this embodiment, the carbapenem antibiotic is imipenem.

A method of preventing a gram negative and/or a gram positive bacterial infection comprising administration of a prophylactically effective amount of a compound of formula I, or a pharmaceutically acceptable salt thereof, and a prophylactically effective amount of a β-lactam antibiotic, or a pharmaceutically acceptable salt thereof, to a patient in need of treatment. In one embodiment the β-lactam antibiotic is selected from: a penicillin antibiotic, a cephamycin antibiotic, a cephalosporin antibiotic or a carbapenem antibiotic. In another embodiment, the β-lactam antibiotic is selected from: a penicillin antibiotic and a carbapenem antibiotic. In another embodiment, the β-lactam antibiotic is a penicillin antibiotic. In a class of this embodiment, the penicillin antibiotic is dicloxacillin. In another class of this embodiment, the bacterial infection is a gram positive bacterial infection and the penicillin antibiotic is dicloxacillin. In another embodiment, the β-lactam antibiotic is a carbapenem antibiotic. In a class of this embodiment, the carbapenem antibiotic is imipenem. In another class of this embodiment, the bacterial infection is a gram positive and/or a gram negative bacterial infection and the carbapenem antibiotic is imipenem. In another class of this embodiment, the bacterial infection is a gram positive bacterial infection and the carbapenem antibiotic is imipenem. In another class of this embodiment, the bacterial infection is a gram negative bacterial infection and the carbapenem antibiotic is imipenem.

A method of preventing a MRSA infection comprising administration of a prophylactically effective amount of a compound of formula I, or a pharmaceutically acceptable salt thereof, and a prophylactically effective amount of a β-lactam antibiotic, or a pharmaceutically acceptable salt thereof, to a patient in need of treatment. In one embodiment the β-lactam antibiotic is selected from: a penicillin antibiotic, a cephamycin antibiotic, a cephalosporin antibiotic or a carbapenem antibiotic. In another embodiment, the β-lactam antibiotic is selected from: a penicillin antibiotic and a carbapenem antibiotic. In another embodiment, the β-lactam antibiotic is a penicillin antibiotic. In a class of this embodiment, the penicillin antibiotic is dicloxacillin. In another embodiment, the β-lactam antibiotic is a carbapenem antibiotic. In a class of this embodiment, the carbapenem antibiotic is imipenem.

A method of preventing a MRSE infection comprising administration of a prophylactically effective amount of a compound of formula I, or a pharmaceutically acceptable salt thereof, and a prophylactically effective amount of a β-lactam antibiotic, or a pharmaceutically acceptable salt thereof, to a patient in need of treatment. In one embodiment the β-lactam antibiotic is selected from: a penicillin antibiotic, a cephamycin antibiotic, a cephalosporin antibiotic or a carbapenem antibiotic. In another embodiment, the β-lactam antibiotic is selected from: a penicillin antibiotic and a carbapenem antibiotic. In another embodiment, the β-lactam antibiotic is a penicillin antibiotic. In a class of this embodiment, the penicillin antibiotic is dicloxacillin. In another embodiment, the β-lactam antibiotic is a carbapenem antibiotic. In a class of this embodiment, the carbapenem antibiotic is imipenem.

A method of preventing a bacterial infection by sensitizing the bacteria to the patient's immune system response comprising administration of a prophylactically effective amount of a compound of formula I, or a pharmaceutically acceptable salt thereof, and a prophylactically effective amount of a β-lactam antibiotic, or a pharmaceutically acceptable salt thereof, to a patient in need of treatment. In one embodiment, the bacterial infection is a gram positive bacterial infection. In another embodiment the bacterial infection is a gram negative bacterial infection. In another embodiment, the bacterial infection is a MRSA infection. In another embodiment, the bacterical infection is a MRSE infection. In another embodiment the β-lactam antibiotic is selected from: a penicillin antibiotic, a cephamycin antibiotic, a cephalosporin antibiotic or a carbapenem antibiotic. In another embodiment, the β-lactam antibiotic is selected from: a penicillin antibiotic and a carbapenem antibiotic. In another embodiment, the β-lactam antibiotic is a penicillin antibiotic. In a class of this embodiment, the penicillin antibiotic is dicloxacillin. In another embodiment, the β-lactam antibiotic is a carbapenem antibiotic. In a class of this embodiment, the carbapenem antibiotic is imipenem.

The invention also includes pharmaceutically acceptable salts of the compounds of formula I, and pharmaceutical compositions comprising the compounds of formula I, or pharmaceutically acceptable salts thereof, and a pharmaceutically acceptable carrier.

The invention also includes pharmaceutically acceptable salts of the compounds of formula I, and pharmaceutical compositions comprising the compounds of formula I, or pharmaceutically acceptable salts thereof, in combination with a β-lactam antibiotic, and a pharmaceutically acceptable carrier.

Other embodiments of the present invention include the following:

(a) A pharmaceutical composition comprising an effective amount of a compound of Formula I as defined above, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier.

(b) The pharmaceutical composition of (a), further comprising an effective amount of a β-lactam antibiotic.

(c) The pharmaceutical composition of (b), wherein the beta-lactam antibiotic is selected from the group consisting of methicillin, oxacillin, penicillin G, dicloxacillin, naficillin, cefepime, cefoxitin, cefuroxime, imipenem, doripenem, meropenem, and tebipenem.

(d) The pharmaceutical composition of (b), wherein the beta-lactam antibiotic is selected from the group consisting of: imipenem and dicloxacillin.

(e) The pharmaceutical composition of (b), wherein the β-lactam antibiotic is imipenem.

(f) The pharmaceutical composition of (b), wherein the β-lactam antibiotic is dicloxacillin.

(g) A combination of therapeutically effective amounts of a compound of Formula I as defined above, or a pharmaceutically acceptable salt thereof, and a β-lactam antibiotic.

(h) The combination of (g), wherein the beta-lactam antibiotic is selected from the group consisting of methicillin, oxacillin, penicillin G, dicloxacillin, naficillin, cefepime, cefoxitin, cefuroxime, imipenem, doripenem, meropenem, and tebipenem.

(i) The combination of (g), wherein the beta-lactam antibiotic is selected from the group consisting of imipenem, and dicloxacillin.

(j) The combination of (g), wherein the β-lactam antibiotic is imipenem.

(k) The combination of (g), wherein the β-lactam antibiotic is dicloxacillin.

(l) A method for treating a bacterial infection comprising administering to a subject in need of such treatment a therapeutically effective amount of a compound of Formula I, or a pharmaceutically acceptable salt thereof, optionally in combination with an effective amount of a beta-lactam antibiotic.

(m) A method for treating a bacterial infection comprising administering to a subject in need of such treatment a therapeutically effective amount of the composition of (a), (b), (c), (d), (e), (f), (g), (i), (j) and (k).

(n) A method for treating a bacterial infection comprising administering to a subject in need of such treatment a therapeutically effective amount of the combination (j), and (k).

(o) The method of treating a bacterial infection as set forth in (m), or (n), wherein the bacterial infection is due to gram positive bacteria and/or gram negative bacteria.

(p) The method of treating a bacterial infection as set forth in (m), or (n), wherein the bacterial infection is due to methicillin-resistant S. aureas (MRSA) or methicillin-resistant S. epidermidis (MRSE).

(q) A method for preventing a bacterial infection comprising administering to a subject in need of such treatment a prophylactically effective amount of a compound of Formula I, or a pharmaceutically acceptable salt thereof, optionally in combination with an effective amount of a beta-lactam antibiotic.

(r) A method for preventing a bacterial infection comprising administering to a subject in need of such treatment a prophylactically effective amount of the composition of (a), (b), (c), (d), (e), (f), (g), (i), (j) and (k).

(s) A method for preventing a bacterial infection comprising administering to a subject in need of such treatment a prophylactically effective amount of the combination (j), and (k).

(t) The method of preventing a bacterial infection as set forth in (q), or (r), wherein the bacterial infection is due to gram positive bacteria and/or gram negative bacteria.

(u) The method of preventing a bacterial infection as set forth in (q), or (r), wherein the bacterial infection is due to methicillin-resistant S. aureas (MRSA) or methicillin-resistant S. epidermidis (MRSE).

The compounds of the present invention, and pharmaceutically acceptable salts thereof, may also be useful to prevent MRSA and MRSE infections in a subject. For example, TarO inhibitors may be used to coat medical devices such as catheters, shunts, and prosthetic devices to prevent infections by preventing the bacteria from forming biofilms.

The present invention also includes a compound of Formula I, or a pharmaceutically acceptable salt thereof, (i) for use in, (ii) for use as a medicament for, or (iii) for use in the preparation or manufacture of a medicament for treating bacterial infection. In these uses, the compounds of the present invention can optionally be employed in combination with one or more β-lactam antibiotics.

The compounds of the present invention may be used for the manufacture of a medicament which may be useful for treating one or more of these diseases, alone or in combination with a β-lactam antibiotic, including but not limited to, a penicillin antibiotic, a cephamycin antibiotic, a cephalosporin antibiotic or a carbapenem antibiotic:

-   -   (1) bacterial infections;     -   (2) gram negative bacterial infections;     -   (3) gram positive bacterial infections;     -   (4) methicillin-resistant S. aureus (MRSA) infections; and     -   (4) methicillin-resistant S. epidermidis (MRSE) infections.

The compounds of the present invention may be used for manufacturing a medicament for the treatment of one or more of these diseases in combination with a β-lactam antibiotic, such as a penicillin antibiotic, a cephamycin antibiotic, a cephalosporin antibiotic or a carbapenem antibiotic:

-   -   (1) bacterial infections;     -   (2) gram negative bacterial infections;     -   (3) gram positive bacterial infections;     -   (4) methicillin-resistant S. aureus (MRSA) infections; and     -   (4) methicillin-resistant S. epidermidis (MRSE) infections.

Further, the compounds of the present invention may be used for manufacturing a medicament for the treatment of one or more of these diseases in combination with a β-lactam antibiotic selected from: imipenem and dicloxacillin:

-   -   (1) bacterial infections;     -   (2) gram negative bacterial infections;     -   (3) gram positive bacterial infections;     -   (4) methicillin-resistant S. aureus (MRSA) infections; and     -   (4) methicillin-resistant S. epidermidis (MRSE) infections.

A compound of formula I of the present invention, or a pharmaceutically acceptable salt thereof, may be used in the manufacture of a medicament for the treatment of bacterial infections in a human or other mammalian patient.

A compound of formula I of the present invention, or a pharmaceutically acceptable salt thereof, may be used in the manufacture of a medicament for the treatment of gram negative bacterial infections in a human or other mammalian patient.

A compound of formula I of the present invention, or a pharmaceutically acceptable salt thereof, may be used in the manufacture of a medicament for the treatment of gram positive bacterial infections in a human or other mammalian patient.

In particular, a compound of formula I of the present invention, or a pharmaceutically acceptable salt thereof, may be used in the manufacture of a medicament for the treatment of MRSA infections in a human or other mammalian patient. In particular, a compound of formula I of the present invention, or a pharmaceutically acceptable salt thereof, may be used in the manufacture of a medicament for the treatment of MRSE infections in a human or other mammalian patient.

Other medical uses of the compounds of the present invention are described herein.

The phrase “treatment of a bacterial infection” means the administration of a compound of the present invention, or a pharmaceutically acceptable salt thereof, alone or in combination with another antibiotic, such as but not limited to a β-lactam antibiotic, to a subject, such as a human or mammal, infected with bacteria. The phrase “treatment of a bacterial infection” as used herein includes but is not limited to, treatment of a gram negative bacterial infection, treatment of a gram positive bacterial infection, treatment of a MRSA infection, and treatment of a MRSE infection.

The phrase “bacterial infection” means an infection caused by bacteria.

The phrase “gram negative bacterial infection” means an infection caused by gram negative bacteria.

The phrase “gram positive bacterial infection” means an infection caused by gram positive bacteria.

The phrase “MRSA infection” means an infection caused by MRSA bacteria.

The phrase “MRSE infection” means an infection caused by MRSE bacteria.

One outcome of treatment may be killing the bacteria in the bacterial infection. Another outcome of treatment may be decreasing the number of bacteria. Another outcome of treatment may be inducing cell death in a bacterium, in particular in a gram positive bacterium. Another outcome of treatment may be reducing the proliferation of bacterium, in particular gram positive bacterium. Another outcome of treatment may be inducing cell death in a bacterium, in particular in a gram negative bacterium. Another outcome of treatment may be reducing the proliferation of bacterium, in particular gram negative bacterium. Another outcome of treatment may be decreasing bacterial levels in a subject. Another outcome of treatment may be decreasing the bacterial load. Another outcome of treatment may be increasing β-lactam antibiotic effectiveness against the bacteria. Another outcome of treatment may be decreasing bacterial resistance to β-lactam antibiotics. Another outcome of treatment may be increasing bacterial susceptibility to treatment with β-lactam antibiotics. Another outcome of treatment may be to decrease the viability of the bacteria. Another outcome of treatment may be to inhibit bacterial growth. Another outcome of treatment may be to kill >95% of the bacteria. Another outcome of treatment may be to kill >80% of the bacteria. Another outcome of treatment may be to kill >50% of the bacteria. Another outcome of treatment may be to kill >20% of the bacteria. Another outcome of treatment may be to kill >10% of the bacteria. Another outcome of treatment may be to kill enough bacteria in a subject to enable the subject's immune system to kill the bacteria. Another outcome of treatment may be to sensitize bacteria to the subject's immune system response.

Another outcome of treatment may be achieving the clinical breakpoint of β-lactam antibiotics established by CLSI (the Clinical and Laboratory Standard Institute USA), or the maximum concentration at which a specific bacterium is designated as susceptible or resistant to the antibiotic. The antibiotic clinical breakpoint definitions are determined and published yearly by the Clinical and Laboratory Standard Institute USA (CLSI). The current clinical breakpoint for imipenem is 4 μg/ml for the susceptibility/resistance profile of Staphylococci. The current clinical breakpoint for dicloxacillin is 8 μg/ml for the susceptibility/resistance profile of Staphylocci.

Another outcome of treatment may be restoring the efficacy of β-lactam antibiotics against methicillin resistant Staphylococci. Another outcome of treatment may be restoring the efficacy of imipenem against MRSA and/or MRSE. Another outcome of treatment may be restoring the efficacy of dicloxacillin against MRSA and/or MRSE. Another outcome of treatment may be a decrease in the number of symptoms of a bacterial infection. Another outcome of treatment may be the reduction in the duration, severity, or frequency of one or more symptoms of a bacterial infection.

Symptoms of a bacterial infection differ depending on the specific population of gram negative and/or gram positive bacteria present in the subject and the site (e.g. tissue in the subject) where the bacteria are located. General symptoms of a gram negative and/or a gram positive bacterial infection include but are not limited to: fever, swelling, pain, and discharge in the infected area. Additional symptoms may include sore throat, sinus infection, pharyngitis, nasal discharge, headaches, nausea, stomach pain, stomach inflammation, dehydration, peptic ulcer, stomach ulcer, indigestion, meningitis, lethargy, gatigue, stiffness in neck and back, shaking, low blood pressure, redness in the eye, watery or itchy eyes, blurred vision, abdominal cramping, vomiting, weakness, sensory loss, chills, difficulty breathing, chest pain, stuffy nose, congestion, increased heartbeat, discomfort, rash, skin discoloration, strong urge to urinate, burning sensation during urination, blood in urine, cloudy urine, strong-smelling urine, black tarry or bloody stools, diarrhea, loss of bowel control, swollen lymph nodes, confusion or disorientation, yeast infection, bacterial baginosis, sepsis, painful acne, and boils. Additional symptoms of bacterial infections are known in the art.

The term “bacterial load” means the measurable quantity of bacteria in a subject or patient. The phrase “decreasing bacterial load” includes decreasing gram negative bacterial load; decreasing gram positive bacterial load; decreasing MRSE bacterial load; and decreasing MRSA bacterial load.

The phrase “increasing β-lactam antibiotic effectiveness” means the ability of a compound of the present invention to increase or restore the ability of β-lactam antibiotics to treat bacterial infections, including but not limited to gram positive bacterial infections, MRSA infections and MRSE infections, when administered in combination with a β-lactam antibiotic.

The phrases “increase bacterial susceptibility to treatment with a β-lactam antibiotic” and “decreasing bacterial resistance to β-lactam antibiotics” mean that when the bacteria is treated with a combination of a compound of the present invention and a β-lactam antibiotic, less of the β-lactam antibiotic is required to reach 95% inhibition of the bacteria (or MITC₉₅) than when the β-lactam antibiotic is administered alone.

The phrase “decreasing bacterial resistance to β-lactam antibiotics” includes decreasing gram negative bacteria resistance to β-lactam antibiotics; decreasing gram positive bacteria resistance to β-lactam antibiotics; decreasing MRSE resistance to β-lactam antibiotics; and decreasing MRSA resistance to β-lactam antibiotics.

The term “antibiotic” refers to a compound or composition which decreases the viability of a microorganism or bacteria, or which inhibits the growth or proliferation of a microorganism or bacteria. The phrase “inhibits the growth or proliferation” means increasing the generation time (i.e., the time required for the bacterial cell to divide or for the population to double).

The terms “beta-lactam antibiotic” and “β-lactam antibiotic” refer to a compound with antibiotic properties that contains a beta-lactam ring in their molecular structures. β-lactam antibiotics that may be suitable for use in combination with the compounds of the present invention include, but are not limited to: penicillin antibiotics, cephamycin antibiotics, cephalosporin antibiotics, and carbapenem antibiotics.

The terms “MRSA infection” as used herein means a methicillin-resistant Staphylococcus aureus infection.

The terms “MRSE infection” as used herein means a methicillin-resistant Staphylococcus epidermidis infection.

The terms “administration of” and or “administering a” compound should be understood to mean providing a compound of the invention or a prodrug of a compound of the invention to the individual or mammal in need of treatment. Administration includes providing the compound of the invention or a prodrug of a compound of the invention to the individual or mammal in need of treatment, alone or in combination with a β-lactam.

The administration of the compound of structural formula I in order to practice the present methods of therapy is carried out by administering an effective amount of the compound of structural formula I to the mammal in need of such treatment or prophylaxis. The need for a prophylactic administration according to the methods of the present invention is determined via the use of well known risk factors. The effective amount of an individual compound is determined, in the final analysis, by the physician or veterinarian in charge of the case, but depends on factors such as the exact disease to be treated, the severity of the disease and other diseases or conditions from which the patient suffers, the chosen route of administration other drugs and treatments which the patient may concomitantly require, and other factors in the physician's judgment.

The usefulness of the present compounds in these diseases or disorders may be demonstrated in animal disease models that have been reported in the literature.

Administration and Dose Ranges

Any suitable route of administration may be employed for providing a mammal, especially a human, with an effective dose of a compound of the present invention. For example, oral, rectal, topical, parenteral, ocular, pulmonary, nasal, intravenous, and the like may be employed. Dosage forms include tablets, troches, dispersions, suspensions, solutions, capsules, creams, ointments, aerosols, and the like. Preferably compounds of the present invention are administered orally.

In the treatment or prevention of conditions which require inhibition of TarO activity, an appropriate dosage level will generally be about 0.01 to 500 mg per kg patient body weight per day which can be administered in single or multiple doses. Preferably, the dosage level will be about 0.1 to about 250 mg/kg per day; more preferably about 0.5 to about 100 mg/kg per day. A suitable dosage level may be about 0.01 to 250 mg/kg per day, about 0.05 to 100 mg/kg per day, or about 0.1 to 50 mg/kg per day. Within this range the dosage may be 0.05 to 0.5, 0.5 to 5 or 5 to 50 mg/kg per day. For oral administration, the compositions are preferably provided in the form of tablets containing 1.0 to 1000 mg of the active ingredient, particularly 1.0, 5.0, 10.0, 15.0, 20.0, 25.0, 50.0, 75.0, 100.0, 150.0, 200.0, 250.0, 300.0, 400.0, 500.0, 600.0, 750.0, 800.0, 900.0, and 1000.0 mg of the active ingredient for the symptomatic adjustment of the dosage to the patient to be treated. The compounds may be administered on a regimen of 1, 2, 3, 4, 5 or 6 times per day, preferably 1, 2, 3, or 4 times a day, more preferably once or twice per day. The compounds may be administered for 1 day to 28 days, or longer until the bacterial infection is treated or prevented.

The compounds of the present invention may be administered intravenously as shots or vaccinations. Intravenous administration of a compound of the present invention can be conducted by reconstituting a powdered form of the compounds with an acceptable solvent. Suitable solvents include, for example, saline solutions (e.g. 90% sodium chloride injection) and sterile water (e.g. Sterile Water for Injection, Bacteriostatic Water for Injection with methylparaben and propylparaben). The powdered form of the compound can be obtained by lyophilization of a solution of the compound, after which the powder can be stored (e.g. in a sealed vial) at or below room temperature until it is reconstituted. The concentration of the compound in the reconstituted IV solution can be, for example, in a range of from about 0.1 mg/mL to about 20 mg/mL.

For intravenous administration, the compositions are preferably provided in the form of an intravenous (IV) solution containing 1.0 to 1000 mg of the active ingredient, particularly 1.0, 5.0, 10.0, 15.0, 20.0, 25.0, 50.0, 75.0, 100.0, 150.0, 200.0, 250.0, 300.0, 400.0, 500.0, 600.0, 750.0, 800.0, 900.0, and 1000.0 mg of the active ingredient for the symptomatic adjustment of the dosage to the patient to be treated. The intravenous solution may be administered on a regimen of 1, 2, 3, 4, 5 or 6 times per day, preferably 1, 2, 3, or 4 times a day, more preferably once or twice per day. The compounds may be administered for 1 day to 28 days, or longer until the bacterial infection is treated or prevented.

When treating or preventing bacterial infections, including but not limited to MRSA and MRSE, or other diseases for which compounds of the present invention are indicated, generally satisfactory results are obtained when the compounds of the present invention are administered at a daily dosage of from about 0.01 mg to about 500 mg per kilogram of animal body weight, preferably given as a single daily dose or in divided doses two to six times a day, or in sustained release form. This dosage regimen may be adjusted to provide the optimal therapeutic response.

It will be understood, however, that the specific dose level and frequency of dosage for any particular patient may be varied and will depend upon a variety of factors including the activity of the specific compound employed, the metabolic stability and length of action of that compound, the age, body weight, general health, sex, diet, mode and time of administration, rate of excretion, drug combination, the severity of the particular condition, and the host undergoing therapy.

The compounds of this invention may be used in pharmaceutical compositions comprising (a) the compound(s) or pharmaceutically acceptable salts thereof, and (b) a pharmaceutically acceptable carrier. The compounds of this invention may be used in pharmaceutical compositions that include one or more other active pharmaceutical ingredients. The compounds of this invention may also be used in pharmaceutical compositions in which the compound of the present invention or a pharmaceutically acceptable salt thereof is the only active ingredient.

The term “composition,” as in pharmaceutical composition, is intended to encompass a product comprising the active ingredient(s), and the inert ingredient(s) that make up the carrier, as well as any product which results, directly or indirectly, from combination, complexation or aggregation of any two or more of the ingredients, or from dissociation of one or more of the ingredients, or from other types of reactions or interactions of one or more of the ingredients. Accordingly, the pharmaceutical compositions of the present invention encompass any composition made by admixing a compound of the present invention and a pharmaceutically acceptable carrier.

Combinations

Compounds of the present invention may be used in combination with other drugs that may also be useful in the treatment or amelioration of the diseases or conditions for which compounds of the present invention are useful. Such other drugs may be administered, by a route and in an amount commonly used therefor, contemporaneously or sequentially with a compound of the present invention. In the treatment of patients who have bacterial infections, including but not limited to antibiotic resistant gram negative bacterial infections, gram positive bacterial infections, MRSA infections and MRSE infections, and co-morbidities that accompany these diseases, more than one drug is commonly administered. The compounds of this invention may generally be administered to a patient who is already taking one or more other drugs for these conditions. Often the compounds will be administered to a patient who is already being treated with one or more antibiotic compounds, or in combination with one or more antibiotics, such as β-lactam antibiotics, when the patient's bacterial levels are not adequately responding to treatment.

When a compound of the present invention is used contemporaneously with one or more other drugs, a pharmaceutical composition in unit dosage form containing such other drugs and the compound of the present invention is preferred. However, the combination therapy also includes therapies in which the compound of the present invention and one or more other drugs are administered on different overlapping schedules. It is also contemplated that when used in combination with one or more other active ingredients, the compound of the present invention and the other active ingredients may be used in lower doses than when each is used singly. Accordingly, the pharmaceutical compositions of the present invention include those that contain one or more other active ingredients, in addition to a compound of the present invention.

It is generally advantageous to use a compound of Formula I in admixture or conjunction with a beta-lactam antibiotic, such as a carbapenem antibiotic, a penicillin antibiotic, a cephalosporin antibiotic, a cephamycin antibiotic, or another β-lactam antibiotic, or a prodrug thereof. The compound of Formula I and the β-lactam antibiotic can be administered separately (at the same time or as different times) or in the form of a single composition containing both active ingredients.

Examples of beta-lactam antibiotics that may be administered, separately or in the same pharmaceutical composition, in combination with a compound of the formulas described herein include, but are not limited to:

-   -   (1) penicillin antibiotics, including but not limited to,         methicillin, oxacillin, penicillin G, dicloxacillin and         naficillin;     -   (2) cephamycin antibiotics, including but not limited to,         cefepime and cefoxitin;     -   (3) cephalosporin antibiotics, including but not limited to,         cefuroxime, ceftiofur and cefquinome; and     -   (4) carbapenem antibiotics, including but not limited to,         imipenem, doripenem, meropenem, and tebipenem.

Other suitable beta-lactam antibiotics that may be administered in combination with a compound of the present invention, and either administered separately or in the same pharmaceutical composition are summarized below.

Carbapenem antibiotics suitable for co-administration with compounds of the present invention include imipenem, meropenem, doripenem, tebipenem, biapenem, (4R, 5S, 6S)-3-[3S, 5S)-5-(3-carboxyphenyl-carbamoyl)pyrrolidin-3-ylthio]-6-(1R)-1-hydroxyethyl]-4-methyl-7-oxo-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylic acid, (1S, 5R, 6S)-2-(4-(2-(((carbamoylmethyl)-1,4-diazoniabicyclo[2.2.2]oct-1-yl)-ethyl(1,8-naphthosultam)methyl)-6-[1(R)-hydroxyethyl]-1-methylcarbapen-2-em-3-carboxylate chloride, BMS181139 ([4R-[4alpha, 5beta, 6beta(R*)]]-4-[2-[(aminoiminomethyl)amino]ethyl]-3-[(2-cyanoethyl)thio]-6-(1-hydroxyethyl)-7-oxo-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylic acid), B02727 ([4R-3[3S*,5S*(R*)], 4 alpha, 5beta, 6beta(R*)]]-6-(1-hydroxyethyl)-3-[[5-[1-hydroxy-3-(methylamino)propyl]-3-pyrrolidinyl]thio]-4-methyl-7-oxo-1-azabicyclo[3.2.0] hept-2-ene-2-carboxylic acid monohydrochloride), E1010 ((1R, 5S, 6S)-6-[1(R)-hydroxymethyl]-2-[2(S)-[1(R)-hydroxy-1-[pyrrolidin-3(R)-yl] methyl]pyrrolidin-4(S)-ylsulfanyl]-1-methyl-1-carba-2-penem-3-carboxylic acid hydrochloride) and 54661 ((1R,5S,6S)-2-[(3S,5S)-5-(sulfamoylaminomethyl) pyrrolidin-3-yl]thio-6-[(1R)-1-hydroxyethyl]-1-methylcarbapen-2-em-3-carboxylic acid), (1S,5R,6S)-1-methyl-2-{7-[4-(aminocarbonylmethyl)-1,4-diazoniabicyclo(2.2.2)octan-1yl]-methyl-fluoren-9-on-3-yl}-6-(1R-hydroxyethyl)-carbapen-2-em-3 carboxylate chloride.

Penicillin antibiotics suitable for co-administration with compounds of the present invention include dicloxacillin, methicillin, oxacillin, penicillin G, naficillin, benzylpenicillin, phenoxymethylpenicillin, carbenicillin, azidocillin, propicillin, ampicillin, amoxicillin, epicillin, ticarcillin, cyclacillin, pirbenicillin, azlocillin, mezlocillin, sulbenicillin, piperacillin, and other known penicillins. The penicillins may be used in the form of pro-drugs thereof; for example as in vivo hydrolysable esters, for example the acetoxymethyl, pivaloyloxymethyl, α-ethoxycarbonyloxy-ethyl and phthalidyl esters of ampicillin, benzylpenicillin and amoxicillin; as aldehyde or ketone adducts of penicillins containing a 6-α-aminoacetamido side chain (for example hetacillin, metampicillin and analogous derivatives of amoxicillin); and as esters of carbenicillin and ticarcillin, for example the phenyl and indanyl α-esters.

Cephalosporin antibiotics suitable for co-administration with compound of the present invention include cefuroxime, cefatrizine, cephaloridine, cephalothin, cefazolin, cephalexin, cephacetrile, cephapirin, cephamandole nafate, cephradine, 4-hydroxycephalexin, cephaloglycin, cefoperazone, cefsulodin, ceftazidime, cefmetazole, cefotaxime, ceftriaxone, ceftiofur and cefquinome; and other known cephalosporins, all of which may be used in the form of pro-drugs thereof.

Cephamycin antibiotics suitable for co-administration with compound of the present invention include cefepime, cefoxitin, cefotetan and cefmetazole, all of which may be used in the form of pro-drugs thereof.

In one embodiment, the antibiotic co-administered with a compound of the present invention is selected from: imipenem and dicloxacillin.

In another embodiment, the antibiotic co-administered with a compound of the present invention is a carbapenem antibiotic selected from: imipenem, meropenem, doripenem and tebipenem.

In another embodiment, the antibiotic co-administered with a compound of the present invention is a penicillin antibiotic selected from: methicillin, oxacillin, penicillin G, dicloxacillin, naficillin, ampicillin, amoxicillin, carbenicillin, piperacillin, azlocillin, mezlocillin, and ticarcillin, or pharmaceutically acceptable salts thereof. In another embodiment, the antibiotic co-administered with a compound of the present invention is a penicillin antibiotic selected from: methicillin, oxacillin, penicillin G, dicloxacillin, and naficillin, or pharmaceutically acceptable salts thereof. Such penicillins can optionally be used in the form of their pharmaceutically acceptable salts, for example their sodium salts. Ampicillin or amoxicillin can alternatively be employed in the form of fine particles of the zwitterionic form (generally as ampicillin trihydrate or amoxicillin trihydrate) for use in an injectable or infusable suspension. In an aspect of this embodiment, the penicillin co-administered with a compound of the present invention is amoxicillin, optionally in the form of its sodium salt or the trihydrate.

In another embodiment, the antibiotic co-administered with a compound of the present invention is a cephalosporin antibiotic selected from: cefuroxime, cefotaxime, ceftriaxone and ceftazidime, or a pharmaceutically acceptable salts thereof. In another embodiment, the antibiotic co-administered with a compound of the present invention is the cephalosporin antibiotic cefuroxime, or a pharmaceutically acceptable salt thereof.

In another embodiment, the antibiotic co-administered with a compound of the present invention is a cephamycin antibiotic selected from: cefepime, cefoxitin, cefotetan and cefmetazole, all of which may be used in the form of pro-drugs thereof. In another embodiment, the antibiotic co-administered with a compound of the present invention is a cephamycin antibiotic selected from: cefepime and cefoxitin, all of which may be used in the form of pro-drugs thereof.

The compounds of the present invention, or pharmaceutically acceptable salts thereof, in combination with a β-lactam antibiotic, including but not limited to imipenem and dicloxacillin, may provide bactericidal synergy in treating bacterial infections in a subject. When co-administered with a β-lactam antibiotic, the combination of the compound of the invention and the β-lactam antibiotic can provide a synergistic bactericical effect.

The terms “synergistic bactericidal effect” and “bactericidal synergy” indicate that the bactericidal effect produced when a β-lactam antibiotic is administered in combination with a compound of the present invention is greater than the bactericidal effect produced when the (3-lactam antibiotic is administered alone, or when a compound of the present invention is administered alone. The “synergistic bactericidal effect” and “bactericidal synergy” may represent a significant reduction in minimum inhibition concentration (MIC) values for a beta-lactam as a single agent. As a result, less β-lactam antibiotic is required to reach 95% inhibition (MITC₉₅) of the bacteria when used in combination with a compound of the present invention. The term bactericidal effect includes but is not limited to bacteria death or the amount of bacteria killed.

The compositions and combinations of the present invention are suitably administered in therapeutically effective amounts. The term “therapeutically effective amount” as used herein means that amount of active compound or pharmaceutical agent that elicits the biological or medicinal response in a tissue, system, animal or human that is being sought by a researcher, veterinarian, medical doctor or other clinician. In one embodiment, the effective amount is a “therapeutically effective amount” for the alleviation of the symptoms of the disease or condition being treated (e.g., bacterial infection and/or bacterial drug resistance). In another embodiment, the effective amount is a “prophylactically effective amount” for prophylaxis of the symptoms of the disease or condition being prevented (e.g., bacterial infection and/or bacterial drug resistance. The term “therapeutically effective amount” also includes herein the amount of active compound sufficient to decrease the bacterial level in a subject and thereby elicit the response being sought (i.e., an “inhibition effective amount”). When the active compound (i.e., active ingredient) is administered as the salt, references to the amount of active ingredient are to the free acid or free base form of the compound.

The term “drug resistance” refers to the loss of susceptibility of a drug target, such as bacteria, to drug treatment. The term “resistance” refers to the decrease or loss of inhibitory effect of the drug on the target bacteria.

The present invention also includes a method for inhibiting bacterial growth comprising administering to a bacterial cell culture, or to a bacterially infected cell culture, tissue, or organism, an inhibition effective amount of a compound of Formula I, or a pharmaceutically acceptable salt thereof, alone or in combination with a β-lactam antibiotic. The method can involve administration of a compound of Formula I, or a pharmaceutically acceptable salt thereof, alone or in combination with a β-lactam antibiotic, to an experimental cell culture in vitro to prevent the growth of β-lactam resistant bacteria. The method can alternatively involve administration of a compound of Formula I, or a pharmaceutically acceptable salt thereof, alone or in combination with a β-lactam antibiotic, to a subject including a patient, human or mammal, to prevent or inhibit the growth of β-lactam resistant bacteria in vivo, or to kill β-lactam resistant bacteria in vivo. In these cases the compound of Formula I is typically co-administered with a β-lactam antibiotic.

Compounds of the invention, or a pharmaceutically acceptable salt thereof, alone or in combination with a β-lactam antibiotic, may be employed for the treatment, prevention, prophylaxis or inhibition of bacterial growth or infections due to bacteria that are resistant to β-lactam antibiotics.

More particularly, the bacteria may be β-lactamase positive strains that are highly resistant to β-lactam antibiotics. The terms “slightly resistant” and “highly resistant” are well-understood by those of ordinary skill in the art (see, e.g., Payne et al., Antimicrobial Agents and Chemotherapy 38:767-772 (1994); Hanaki et al., Antimicrobial Agents and Chemotherapy 30:11.20-11.26 (1995)).

Compounds of the invention may be useful in combination with antibiotic agents for the treatment of infections caused by Class C-β-lactamase producing strains, in addition to those infections which are subsumed within the antibacterial spectrum of the antibiotic agent. Examples of class C-β-lactamase producing bacteria are Pseudomonas aeruginosa, Enterobacter cloacae, Klebsiella pneumoniae, Escherichia coli and Acinetobacter baumannii.

The present invention also provides a method for the treatment or prevention of a TarO mediated disease, which method comprises administration to a patient in need of such treatment or at risk of developing a TarO mediated disease of an amount of a compound of formula I, or a pharmaceutically acceptable salt thereof, and an amount of one or more active ingredients, such that together they give effective relief.

In a further aspect of the present invention, there is provided a pharmaceutical composition comprising a compound of formula I, or a pharmaceutically acceptable salt thereof, and one or more active ingredients, together with at least one pharmaceutically acceptable carrier or excipient.

Thus, according to a further aspect of the present invention there is provided the use of a compound of formula I, or a pharmaceutically acceptable salt thereof, and one or more active ingredients for the manufacture of a medicament for the treatment or prevention of a TarO mediated disease. In a further or alternative aspect of the present invention, there is therefore provided a product comprising a compound of formula I, or a pharmaceutically acceptable salt thereof, and one or more active ingredients as a combined preparation for simultaneous, separate or sequential use in the treatment or prevention of a TarO mediated disease. Such a combined preparation may be, for example, in the form of a twin pack.

It will be appreciated that for the treatment or prevention of bacterial infections, gram negative bacterial infections, gram positive bacterial infections, MRSA infections, MRSE infections, and related bacterial infections, a compound of formula I, or a pharmaceutically acceptable salt thereof, may be used in conjunction with another pharmaceutical agent effective to treat the bacterial infection.

The present invention also provides a method for the treatment or prevention of bacterial infections, gram negative bacterial infections, gram positive bacterial infections, MRSA infections, MRSE infections, and related bacterial infections, which method comprises administration to a patient in need of such treatment an amount of compound of formula I, or a pharmaceutically acceptable salt thereof, and an amount of another pharmaceutical agent effective to treat that bacterial infection, such that together they give effective relief.

The present invention also provides a method for the treatment or prevention of bacterial infections, gram negative bacterial infections, gram positive bacterial infections, MRSA infections, MRSE infections, and related bacterial infections, which method comprises administration to a patient in need of such treatment an amount of a compound of formula I, or a pharmaceutically acceptable salt thereof, and an amount of a β-lactam antibiotic useful in treating that particular bacterial infection, such that together they give effective relief.

The compounds of formula I, or a pharmaceutically acceptable salt thereof, may be useful in combination with β-lactam antibiotics, such as, but not limited to, imipenem and dicloxacillin, for the treatment of bacterial infections, particularly antibiotic resistant gram negative bacterial infections and/or gram positive bacterial infections such as methicillin-resistant Staphylocuccus aureus (MRSA) infections.

The term “therapeutically effective amount” means the amount the compound of structural formula I that will elicit the biological or medical response of a tissue, system, animal or human that is being sought by the researcher, veterinarian, medical doctor or other clinician, which includes alleviation of the symptoms of the disorder being treated. In one embodiment, the therapeutically effective amount as used herein means that amount of the compound of the present invention that alleviates the symptoms of the bacterial infection or bacterial drug resistance when administered alone or in combination with a beta-lactam antibiotic.

The novel methods of treatment and prevention of this invention are for disorders known to those skilled in the art. The term “patient” as used herein means a human or mammal. The term “subject” as used herein means a human, mammal or cell. The term “mammal” includes humans, companion animals such as dogs and cats, and livestock such as cattle, swine and poultry. The term cell includes cells in a cell culture.

The weight ratio of the compound of the Formula I to the second active ingredient may be varied and will depend upon the effective dose of each ingredient. Generally, an effective dose of each will be used. Thus, for example, when a compound of the Formula I is combined with a beta-lactam antibiotic the weight ratio of the compound of the Formula I to the beta-lactam antibiotic will generally range from about 1000:1 to about 1:1000, preferably about 200:1 to about 1:200. Combinations of a compound of the Formula I and other active ingredients will generally also be within the aforementioned range, but in each case, an effective dose of each active ingredient should be used.

Methods of Synthesis of the Compounds of the Present Invention:

The following reaction schemes and Examples illustrate methods which may be employed for the synthesis of the compounds of structural formula I described in this invention. These reaction schemes and Examples are provided to illustrate the invention and are not to be construed as limiting the invention in any manner. All substituents are as defined above unless indicated otherwise. Several strategies based upon synthetic transformations known in the literature of organic synthesis may be employed for the preparation of the compounds of structural formula I. The scope of the invention is defined by the appended claims.

The compounds of the present invention can be prepared according to the procedures of the following Examples, using appropriate materials. The compounds illustrated in the examples are not, however, to be construed as forming the only genus that is considered as the invention. The Examples further illustrate details for the preparation of the compounds of the present invention. Those skilled in the art will readily understand that known variations of protecting groups, as well as of the conditions and processes of the following preparative procedures, can be used to prepare these compounds. It is also understood that whenever a chemical reagent such as a boronic acid or a boronate is not commercially available, such a chemical reagent can be readily prepared following one of numerous methods described in the literature. All temperatures are degrees Celsius unless otherwise noted. Mass spectra (MS) were measured either by electrospray ion-mass spectroscopy (ESMS) or by atmospheric pressure chemical ionization mass spectroscopy (APCI).

Abbreviations

Ac is acetyl; AcO is acetoxy; Alk is alkyl; APCI is atmospheric pressure chemical ionization; aq or aq. is aqueous; Ar is aryl; Boc is tert-butoxycarbonyl; Br is broad; t-BuOK is potassium tert-butoxide; ° C. is degrees celsius; Cbz is benzyloxycarbonyl; CH₂Cl₂ is dichloromethane; CO is carbon monoxide; conc or conc. is concentrated; d is doublet; DAST is (diethylamino)sulfur trifluoride; DIAD is diisopropyl azodicarboxylate; DCM is dichloromethane; DIPEA is N,N-diisopropylethylamine; DMAP is 4-dimethylaminopyridine; DMF is N,N-dimethylformamide; DMSO is dimethylsulfoxide; dppf is 1,1′-Bis(diphenyl-phosphino)ferrocene; equiv. and eq are equivalent; ESI is electrospray ionization; EA or EtOAc is ethyl acetate; Et is ethyl; EtMgBr is ethyl magnesium bromide; EtOH is ethanol; g is gram(s); h or hr or hrs is hour(s); HATU is N-(dimethylamino)-1H-1,2,3-triazolo-[4,5-b]pyridine-1-ylmethylene]-N-methylmethan-aminium hexafluorophosphate N-oxide; HPLC is high pressure liquid chromatography; HOAc or AcOH is acetic acid; kg is kilogram(s); KOH is potassium hydroxide; KOAc is potassium acetate; L is liter; LC-MS is liquid chromatography-mass spectroscopy; LDA is lithium diisopropyl amide; LiOH is lithium hydroxide; m is multiplet; m-CPBA, MCPBA, or mCPBA is meta chloroperbenzoic acid; mL is milliliter; min or mins is minute(s); mol is mole(s); mmol is mmole(s); mg is milligram(s); MeCN is acetonitrile; MeMgBr is methyl magnesium bromide; MeOH is methyl alcohol; MgSO₄ is magnesium sulfate; MS is mass spectroscopy; MsCl or Ms-Cl is methane sulfonyl chloride; N is normal; Na(AcO)₃BH is sodium triacetoxy borohydride; NaHMDS is sodium hexamethyldisilazide; NaOH is sodium hydroxide; Na₂SO₄ is sodium sulfate; NH₄OAc is ammonium acetate; NBS is N-bromo succinamide; NIS is N-iodo succinamide; NMO is 4-methyl morpholine N-oxide; NMP is 1-methyl-2-pyrrolidinone; NMR is nuclear magnetic resonance spectroscopy; PE is petroleum ether; PG is protecting group; P(Cy)₃ is tricyclohexyl phosphine; Pd₂(dba)₃ is tris(dibenzylideneacetone)dipalladium(0); Pd[P(t-Bu)₃]₂ is bis(tri-tert-butylphosphine)palladium (0); Pd(dppf)Cl₂ is [1,1′-bis(diphenylphosphino)-ferrocene]dichloro-palladium (II); PMB is para-methoxybenzyl; PMBC1 is para-methoxybenzyl chloride; PPA is pyrophosphonic acid; prep is preparative; prep. TLC or prep-TLC, or prep TLC is preparative thin layer chromatography; 2^(nd) generation RuPhos precatalyst is chloro(2-dicyclohexylphosphino-2′,6′-diisopropoxy-1,1′-biphenyl)[2-(2′-amino-1,1′-biphenyl)]palladium(II), 0.3 THF adduct; RBF is round bottom flask; RCM is ring closing metathesis reaction; rt or r.t. or RT is room temperature; s is singlet; SFC is supercritical fluid chromatography; s-phos is 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl; t is triplet; TBTU is N,N,N′,N′-Tetramethyl-O-(benzotriazol-1-yl)uronium tetrafluoroborate; TEA is triethyl amine; THF is tetrahydrofuran; Ti(OiPr)₄ is titanium isopropoxide; TFA is trifluoroacetic acid; TLC is thin-layer chromatography; TMSCl is trimethyl silyl chloride; TsCl or TosCl is p-toluene sulfonyl chloride; TsOH is p-toluenesulfonic acid, and xphos is 2-Dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl.

Several methods for preparing the compounds of this invention are illustrated in the following Schemes and Examples. Starting materials are either commercially available or made by known procedures in the literature or as illustrated. The present invention further provides processes for the preparation of compounds of structural formula I as defined above. In some cases the order of carrying out the foregoing reaction schemes may be varied to facilitate the reaction or to avoid unwanted reaction products. The following examples are provided for the purpose of illustration only and are not to be construed as limitations on the disclosed invention. All temperatures are degrees Celsius unless otherwise noted.

Example 1 N-cyclohexyl-N-ethyl-3-(2-(trans-4-ethylcyclohexyl)-5-(hydroxymethyl)-1H-benzo[d]imidazol-1-yl)propanamide

Step 1: Methyl 4-((3-(cyclohexyl(ethyl)amino)-3-oxopropyl)amino)-3-nitrobenzoate Into a vial was added methyl 4-fluoro-3-nitrobenzoate (0.21 g, 1.05 mmol) and 3-amino-N-cyclohexyl-N-ethylpropanamide 2,2,2-trifluoroacetate (0.40 g, 1.26 mmol) and TEA (0.441 ml, 3.16 mmol) in THF (10.5 mL). The reaction was stirred at 25° C. overnight. Then the reaction was poured into a separatory funnel, water was added and the aqueous layer was extracted with DCM (3×15 mL). The combined organic layers were washed with brine (20 mL), dried (Na₂SO₄), filtered and evaporated under reduced pressure to give the title compound, which was used directly for the next reaction without purification. LC-MS m/z [2M+H]⁺ 777.50 (calc'd 777.43).

Step 2: Methyl 3-amino-4-((3-(cyclohexyl(ethyl)amino)-3-oxopropyl)amino)benzoate Into a round bottom flask was added methyl 4-((3-(cyclohexyl(ethyl)amino)-3-oxopropyl)amino)-3-nitrobenzoate (0.41 g, 1.08 mmol) in HCl (1.8 ml, 10.78 mmol), and methanol (5.4 ml) at room temperature. Then zinc (0.28 g, 4.3 mmol) was added and after several minutes the mixture was filtered through a plug of Florisil™. The Florisil™ was washed with DCM (50 mL). The filtrate was washed with aqueous saturated NaCl, then dried (Na₂SO₄), filtered and evaporated under reduced pressure to give the title compound, which was used directly for the next step without further purification. LC-MS m/z [M+H]⁺ 348.89 (calc'd 348.22).

Step 3: Methyl 4-((3-(cyclohexyl(ethyl)amino)-3-oxopropyl)amino)-3-(trans-4-ethylcyclohexane-1-carboxamido)benzoate Into a round bottom flask was added methyl 3-amino-4-((3-(cyclohexyl(ethyl)amino)-3-oxopropyl)amino)benzoate (0.35 g, 1.02 mmol) and TEA (0.43 ml, 3.06 mmol) in DCM (5 mL). To this solution was added dropwsie trans-4-ethylcyclohexanecarbonyl chloride (0.22 g, 1.27 mmol). The solution was concentrated and the resulting residue was purified via flash chromatography (0% to 50% EtOAc in hexane) to give the title compound. LC-MS: M+H 486.47 (calc'd 486.33).

Step 4: Methyl 1-(3-(cyclohexyl(ethyl)amino)-3-oxopropyl)-2-(trans-4-ethylcyclohexyl)-1H-benzo[d]imidazole-5-carboxylate Into a dram vial was added methyl 4-((3-(cyclohexyl(ethyl)-amino)-3-oxopropyl)amino)-3-((trans-4-ethylcyclohexanecarboxamido)-benzoate (0.36 g, 0.38 mmol) in acetic acid (4 ml). The reaction mixture was heated at 90° C. for 4 hours and at room temperature overnight. Then the reaction was diluted with toluene and concentrated. The resulting residue was purified by flash chromatography (0% to 50% EtOAc in hexane) to provide the title compound. LC-MS m/z [M+H]⁺ 469.09 (calc'd 468.31).

Step 5: N-cyclohexyl-N-ethyl-3-(2-(trans-4-ethylcyclohexyl)-5-(hydroxymethyl)-1H-benzo[d]imidazol-1-yl)propanamide Into a round bottom flask was added methyl 1-(3-(cyclohexyl(ethyl)amino)-3-oxopropyl)-2-(trans-4-ethylcyclohexyl)-1H-benzo[d]imidazole-5-carboxylate from Step 4 (0.061 g, 0.13 mmol) in THF (1.3 ml). To the solution was added Superhydride™ (0.33 ml, 0.33 mmol). Then the solution was stirred at 25° C. for 2 h. An additional amount of Superhydride™ (0.33 ml, 0.33 mmol) was added and the reaction was stirred for 2.5 h. Then an additional amount of Superhydride™ (5 equiv.) was added and the solution was again stirred for 2.5 h. Then the reaction solution was quenched by the addition of aqueous saturated NH4C₁ (30 mL). The aqueous layer was separated and extracted with DCM (3×15 mL). The combined organic layers were washed with brine (20 mL), dried (Na₂SO₄), filtered and evaporated under reduced pressure. The resulting residue was purified via reverse phase Gilson HPLC (20-100% CH₃CN/water w/0.05% TFA) to provide the title compound. LC-MS m/z [M+H]⁺ 440.45 (calc'd 440.32).

TABLE 1 The compounds of Examples 2-23 were prepared according to the procedure of Example 1, using the appropriate starting materials. Calc'd Observed Example Mass Mass Number Structure Name M + H⁺ M + H⁺ 2

N-cyclohexyl-N-ethyl- 3-[2-(trans-4- ethylcyclohexyl)-1H- imidazo[4,5-b]pyridin- 1-yl]propanamide 411.31 411.60 3

3-[6-cyano-2-(trans-4- ethylcyclohexyl)-1H- benzimidazol-1-yl]-N- cyclohexyl-N- ethylpropanamide 435.31 435.40 4

N-cyclohexyl-N-ethyl- 3-[2-(trans-4- ethylcyclohexyl)-3H- imidazo[4,5-c]pyridin- 3-yl]propanamide 411.31 411.60 5

3-[5-bromo-2-(trans-4- ethylcyclohexyl)-1H- benzimidazol-1-yl]-N- cyclohexyl-N- ethylpropanamide  488.22; 490.22  488.40; 489.80 6

N-cyclohexyl-N-ethyl- 3-(2-(trans-4- ethylcyclohexyl)-6- fluoro-1H- benzo[d]imidazol-1- yl)propanamide 428.31 428.58 7

N-cyclohexyl-N-ethyl- 3-[2-(trans-4- ethylcyclohexyl)-5- (trifluoromethyl)-1H- benzimidazol-1- yl]propanamide 478.30 478.40 8

3-[6-bromo-2-(trans-4- ethylcyclohexyl)-1H- benzimidazol-1-yl]-N- cyclohexyl-N- ethylpropanamide  488.22; 490.22  488.10; 490.10 9

N-cyclohexyl-N-ethyl- 3-[2-(trans-4- ethylcyclohexyl)-4- fluoro-1H- benzimidazol-1- yl]propanamide 428.31 428.43 10

N-cyclohexyl-N-ethyl- 3-[2-(trans-4- ethylcyclohexyl)-5- fluoro-1H- benzimidazol-1- yl]propanamide 428.31 428.40 11

N-cyclohexyl-N-ethyl- 3-[2-(trans-4- ethylcyclohexyl)-7- fluoro-1H- benzimidazol-1- yl]propanamide 428.31 428.50 12

tert-butyl 3-(1-{3- [cyclohexyl(ethyl)amino]- 3-oxopropyl}-5- fluoro-1H- benzimidazol-2- yl)piperidine-1- carboxylate 501.32 501.40 13

Ethyl 3-(1-{3- [cyclohexyl(ethyl)amino]- 3-oxopropyl}-5- fluoro-1H- benzimidazol-2- yl)piperidine-1- carboxylate 473.29 473.40 14

N-cyclohexyl-N-ethyl- 3-[2-(trans-4- ethylcyclohexyl)-6- (hydroxymethyl)-1H- benzimidazol-1- yl]propanamide 440.33 440.40 15

tert-butyl 3-(1-{3- [cyclohexyl(ethyl)amino]- 3-oxopropyl}-5- fluoro-1H- benzimidazol-2- yl)piperidine-1- carboxylate 501.32 501.60 16

N-cyclohexyl-N-ethyl- 3-[2-(trans-4- ethylcyclohexyl)-5- methoxy-1H- benzimidazol-1- yl]propanamide 440.32 440.40 17

N-cyclohexyl-N-ethyl- 3-[2-(trans-4- ethylcyclohexyl)-1H- imidazo[4,5-c]pyridin- 1-yl]propanamide 411.31 411.40 18

Ethyl 3-(1-{3- [cyclohexyl(ethyl)amino]- 3-oxopropyl}-5- fluoro-1H- benzimidazol-2- yl)piperidine-1- carboxylate 473.29 473.39 19

N-cyclohexyl-N-ethyl- 3-[2-(trans-4- ethylcyclohexyl)-3H- imidazo[4,5-b]pyridin- 3-yl]propanamide 411.31 411.40 20

N-cyclohexyl-3-[4- (difluoromethyl)-2- (trans-4- methylcyclohexyl)-1H- benzimidazol-1-yl]-N- ethylpropanamide 446.29 446.40 21

tert-butyl 3-(1-{3- [cyclohexyl(ethyl)amino]- 3-oxopropyl}-5- fluoro-1H- benzimidazol-2- yl)pyrrolidine-1- carboxylate 487.31 487.82 22

3-[5-cyano-2-(trans-4- ethylcyclohexyl)-1H- benzimidazol-1-yl]-N- cyclohexyl-N- ethylpropanamide 435.31 435.50 23

Ethyl 3-(1-{3- [cyclohexyl(ethyl)amino]- 3-oxopropyl}-6- fluoro-1H- benzimidazol-2- yl)piperidine-1- carboxylate 473.29 473.39

Example 24 N-cyclohexyl-N-ethyl-3-(2-(trans-4-ethylcyclohexyl)-6-phenyl-1H-benzo[d]imidazol-1-yl)propanamide

In a microwave tube, 3-(6-bromo-2-(trans-4-ethylcyclohexyl)-1H-benzo[d]imidazol-1-yl)-N-cyclohexyl-N-ethylpropanamide (40 mg, 0.082 mmol, prepared according to the procedure of Example 1), phenyl boronic acid (11.98 mg, 0.098 mmol), potassium carbonate (45.3 mg, 0.328 mmol) and palladium tetrakis (9.46 mg, 8.19 μmol) in ethanol (1.5 mL) were added and degassed. The reaction mixture was subjected to microwave conditions at 120° C. for 1 h, then cooled to room temperature, and EtOAc was added. The mixture was washed with water and brine, dried over with MgSO₄. After solvent removal, the resulting crude was dissolved in 1.5 mL of DMSO and purified by HPLC (column: Waters Sunfire C18, 5u, 19×100 mm; solvent: gradient range: 10-15% initial to 70-98% final CH₃CN (either 0.1% formic acid or TFA) in water (0.1% formic acid or TFA) 50 mL/min 8 min run time) to give the title compound. LC-MS m/z [M+H]⁺ 486.44 (calc'd 486.35).

TABLE 2 The compounds of Examples 25-32 were prepared according to the procedure of Example 24, using the appropriate starting materials. Calc'd Observed Example Mass Mass Number Structure Name M + H⁺ M + H⁺ 25

N-cyclohexyl-N-ethyl- 3-[2-(trans-4- ethylcyclohexyl)-6-(1- methyl-1H-pyrazol-4- yl)-1H-benzimidazol-1- yl]propanamide 490.35 490.47 26

N-cyclohexyl-3-[5- cyclopropyl-2-(trans-4- ethylcyclohexyl)-1H- benzimidazol-1-yl]-N- ethylpropanamide 450.35 450.60 27

3-[6-(aminomethyl)-2- (trans-4- ethylcyclohexyl)-1H- benzimidazol-1-yl]-N- cyclohexyl-N- ethylpropanamide 439.34 439.30 28

N-cyclohexyl-N-ethyl- 3-{2-(trans-4- ethylcyclohexyl)-6- [(3S)-tetrahydrofuran- 3-ylmethyl]-1H- benzimidazol-1- yl}propanamide 494.37 494.40 29

N-cyclohexyl-N-ethyl- 3-{2-(trans-4- ethylcyclohexyl)-4- [(3S)-tetrahydrofuran- 3-ylmethyl]-1H- benzimidazol-1- yl}propanamide 494.37 494.40 30

N-cyclohexyl-N-ethyl- 3-[2-(trans-4- ethylcyclohexyl)-6-{[4- (2,2,2- trifluoroethyl)piperazin- 1-yl]methyl}-1H- benzimidazol-1- yl]propanamide 590.40 590.48 31

N-cyclohexyl-3-{6- [(3,3-difluoroazetidin- 1-yl)methyl]-2-(trans- 4-ethylcyclohexyl)-1H- benzimidazol-1-yl}-N- ethylpropanamide 515.35 515.42 32

N-cyclohexyl-N-ethyl- 3-[2-(trans-4- ethylcyclohexyl)-4- morpholin-4-yl-1H- benzimidazol-1- yl]propanamide 495.36 495.60

Example 33 3-[2-(cis-4-tert-butylcyclohexyl)-1H-benzimidazol-1-yl]-N-[(1R,2R,4R)-1,7,7-trimethylbicyclo[2.2.1]hept-2-yl]propanamide

Step 1: N-((1R,2R,4R)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-yl)acrylamide Into an 8 dram vial was added exo-(1R)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-amine hydrochloride (0.20 g, 1.05 mmol) in DCM (4 mL). To this solution was added dropwise TEA (0.32 ml, 2.32 mmol). The reaction was stirred at 25° C. for several minutes, then acryloyl chloride (0.09 mL, 1.16 mmol) was added dropwise. The reaction mixture was stirred at 25° C. for 2 h, then diluted with water (20 mL). The aqueous layer was separated and extracted with DCM (3×10 mL). The combined organic layers were washed with saturated NaHCO₃ (10 mL) and brine (10 mL). The organic layer was dried (Na₂SO₄), filtered and the filtrate was evaporated under reduced pressure to give the title compound. LC-MS m/z [M+H]⁺ 208.07 (calc'd 208.16).

Step 2: 2-(cis-4-(tert-butyl)cyclohexyl)-1H-benzo[d]imidazole To a round bottom flask was added PPA (10 g), followed by O-phenylenediamine (300 mg, 2.77 mmol) and cis-4-tert-butylcyclohexanecarboxylic acid (511 mg, 2.77 mmol). The reaction was heated to 200° C. for 4 h, then cooled to rt, and ice was added to the reaction mixture. Then 5N NaOH was added by pipette until the mixture was basic (pH 9), followed by the addition of water (50 mL). The reaction mixture was stirred until the gummy residue became a gray powder, then filtered and dried to give the title compound, which was used without further purification.

Step 3: 3-(2-(cis-4-(tert-butyl)cyclohexyl)-1H-benzo[d]imidazol-1-yl)-N-((1R,2S,4R)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-yl)propanamide To a 2 dram vial was added potassium carbonate (264 mg, 1.91 mmol), N-((1R,2S,4R)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-yl)acrylamide (67.9 mg, 0.33 mmol), 2-(cis-4-(tert-butyl)cyclohexyl)-1H-benzo[d]imidazole (70 mg, 0.27 mmol) and DMF (1.5 mL). The mixture was heated to 120° C. for overnight. After cooling to rt, the resulting crude was filtered and purified directly on reverse phase Gilson HPLC (20% to 100% MeCN/water w/0.05% TFA) to afford the title compound. LC-MS m/z [M+H]⁺ 464.31 (calc'd 464.36).

TABLE 3 The compounds of Examples 34-42 were prepared according to the procedure of Example 33, using the appropriate starting materials. Calc'd Observed Example Mass Mass Number Structure Name M + H⁺ M + H⁺ 34

N-cyclohexyl-N-ethyl- 3-{2-[4-(2,2,2- trifluoroethoxy)phenyl]- 1H-benzimidazol-1- yl}propanamide 474.23 474.23 35

N-cyclohexyl-3-(2- cyclohexyl-1H- benzimidazol-1-yl)-N- ethylpropanamide 382.28 382.20 36

methyl 4-(1-{3- [cyclohexyl(ethyl)amino]- 3-oxopropyl}-1H- benzimidazol-2- yl)benzoate 434.24 434.22 37

3-(2-cyclohexyl-1H- benzimidazol-1-yl)-N- [(1R,2R,4R)-1,7,7- trimethylbicyclo[2.2.1] hept-2-yl]propanamide 408.30 408.30 38

N-cyclohexyl-3-[2-(6- ethoxypyridin-3-yl)- 1H-benzimidazol-1-yl]- N-ethylpropanamide 421.25 421.22 39

N-cyclohexyl-3-(2- cyclohexyl-1H- benzimidazol-1-yl)-N- methylpropanamide 368.26 368.20 40

tert-butyl ({4-[1-(3- oxo-3-{[(1R,4R)-1,7,7- trimethylbicyclo[2.2.1] hept-2- yl]amino}propyl)-1H- benzimidazol-2- yl]cyclohexyl}methyl) carbamate 537.38 537.06 41

tert-butyl 3-[1-(3-oxo- 3-{[(1R,4R)-1,7,7- trimethylbicyclo[2.2.1] hept-2- yl]amino}propyl)-1H- benzimidazol-2- yl]pyrrolidine-1- carboxylate 495.33 495.18 42

N-cyclohexyl-N-ethyl- 3-{2-[4-(1H-1,2,3- triazol-1-yl)phenyl]- 1H-benzimidazol-1- yl}propanamide 443.25 443.23

Example 43 N-cyclohexyl-N-ethyl-3-(2-(1-(4-methoxypyrimidin-2-yl)piperidin-3-yl)-1H-benzo[d]imidazol-1-yl)propanamide

Step 1: tert-butyl 3-(1-(3-(cyclohexyl(ethyl)amino)-3-oxopropyl)-1H-benzo[d]imidazol-2-yl)piperidine-1-carboxylate The title compound of Step 1 was synthesized according to the procedure of Example 33 except for the ring closure reaction, in which HOAc was used instead of PPA. LC-MS m/z [M+H]+483.45 (calc'd 483.33).

Step 2: N-cyclohexyl-N-ethyl-3-(2-(piperidin-3-yl)-1H-benzo[d]imidazol-1-yl)propanamide To a mixture of tert-butyl 3-(1-(3-(cyclohexyl(ethyl)amino)-3-oxopropyl)-1H-benzo[d]imidazol-2-yl)piperidine-1-carboxylate (1.6 g, 3.3 mmol) in DCM (5 mL) was added TFA (2 mL, 26.0 mmol) at room temperature. The reaction mixture was stirred for 19 h. Then the solvent was removed and the resulting residue was dissolved in MeCN, then H₂O was added and the mixture was lyophilized to give the title compound.

Step 3: N-cyclohexyl-N-ethyl-3-(2-(1-(4-methoxypyrimidin-2-yl)piperidin-3-yl)-1H-benzo[d]imidazol-1-yl)propanamide A mixture of N-cyclohexyl-N-ethyl-3-(2-(piperidin-3-yl)-1H-benzo[d]imidazol-1-yl)propanamide TFA salt (40.0 mg, 0.08 mmol), THF (1 mL), cesium carbonate (68.1 mg, 0.21 mmol), 2-chloro-4-methoxypyrimidine (15.1 mg, 0.10 mmol) and 2nd generation RuPhos precatalyst (6.5 mg, 8.37 μmol) in a microwave tube was flushed with nitrogen and heated overnight at 70° C. After cooling to rt, the reaction mixture was diluted with EtOAc, filtered and concentrated. The resulting residue was dissolved in CH₃CN (0.5 mL) and TFA (20 uL) and purified via Gilson reverse phase HPLC (10% to 100% MeCN/H₂O/0.1% TFA) to give the title compound. LC-MS m/z [M+H]⁺ 491.58 (calc'd 491.31).

TABLE 4 The compounds of Examples 44-54 were prepared according to the procedure of Example 43, using the appropriate starting materials. Calc'd Observed Example Mass Mass Number Structure Name M + H⁺ M + H⁺ 44

N-cyclohexyl-N-ethyl- 3-{2-[1-(6- methoxypyridin-2-yl)- 6-methylpiperidin-3- yl]-1H-benzimidazol-1- yl}propanamide 504.33 504.40 45

butyl 3-(1-{3- [cyclohexyl(ethyl)amino]- 3-oxopropyl}-1H- benzimidazol-2- yl)piperidine-1- carboxylate 483.33 483.42 46

N-cyclohexyl-N-ethyl- 3-{2-[1-(3-ethyl-1,2,4- thiadiazol-5- yl)piperidin-3-yl]-1H- benzimidazol-1- yl}propanamide 495.29 495.60 47

N-cyclohexyl-N-ethyl- 3-{2-[1-(6- methoxypyridin-2- yl)piperidin-3-yl]-1H- benzimidazol-1- yl}propanamide 490.31 490.14 48

N-cyclohexyl-N-ethyl- 3-[2-(1-pyridin-2- ylpiperidin-3-yl)-1H- benzimidazol-1- yl]propanamide 460.30 460.27 49

propyl 5-(1-{3- [cyclohexyl(ethyl)amino]- 3-oxopropyl}-1H- benzimidazol-2-yl)-2- methylpiperidine-1- carboxylate 483.31 483.40 50

N-cyclohexyl-N-ethyl- 3-{2-[1-(4- methoxypyrimidin-2- yl)-6-methylpiperidin- 3-yl]-1H-benzimidazol- 1-yl}propanamide 505.32 505.40 51

Propyl 3-(1-{3- [cyclohexyl(ethyl)amino]- 3-oxopropyl}-1H- benzimidazol-2- yl)piperidine-1- carboxylate 469.31 469.43 52

N-cyclohexyl-N-ethyl- 3-{2-[1-(4- methylpyrimidin-2- yl)piperidin-3-yl]-1H- benzimidazol-1- yl}propanamide 475.31 475.36 53

1-methylethyl 3-(1-{3- [cyclohexyl(ethyl)amino]- 3-oxopropyl}-1H- benzimidazol-2- yl)piperidine-1- carboxylate 469.31 469.40 54

N-cyclohexyl-N-ethyl- 3-[2-(6-methyl-1- pyrimidin-2- ylpiperidin-3-yl)-1H- benzimidazol-1- yl]propanamide 475.31 475.60

Example 55 N-cyclohexyl-3-(2-(4,4-difluoropiperidin-1-yl)-1H-benzo[d]imidazol-1-yl)-N-ethylpropanamide

Step 1: 3-(2-chloro-1H-benzo[d]imidazol-1-yl)-N-cyclohexyl-N-ethylpropanamide To a stirred reaction mixture of 2-chloro-1H-benzo[d]imidazole (0.75 g, 4.91 mmol) and N-cyclohexyl-N-ethylacrylamide (1.30 g, 7.17 mmol) in DMF (3 mL) was added potassium carbonate (2.03 g, 14.73 mmol). The reaction mixture was heated to 120° C. for overnight, then cooled to rt, and diluted with EtOAc. The resulting mixture was filtered through a Celite™ bed, which was washed with EtOAc. The filtrate was washed with brine, dried over with MgSO₄, filtered, and the filtrate was dried. The resulting crude product was purified by flash chromatography (0% to 50% EtOAc in hexane) to afford the title compound. LC-MS m/z [M+H]⁺ 334.11 (calc'd 334.16).

Step 2: N-cyclohexyl-3-(2-(4,4-difluoropiperidin-1-yl)-1H-benzo[d]imidazol-1-yl)-N-ethylpropanamide A solution of 3-(2-chloro-1H-benzo[d]imidazol-1-yl)-N-cyclohexyl-N-ethylpropanamide (30.0 mg, 0.09 mmol) and 4,4-difluoropiperidine hydrochloride (300.0 mg, 1.90 mmol) in EtOH (1.5 mL) was heated at 120° C. overnight. Then the reaction mixture was filtered through silica gel pad and washed with EtOAc. Then the solvent was removed and EtOAc (30 mL) was added. The mixture washed with saturated NaHCO₃, brine, dried over with MgSO₄, filtered and dried. The resulting crude product was purified by Gilson reverse phase HPLC (10% to 100% MeCN/H₂O/0.1% TFA) to give the title compound. LC-MS m/z [M+H]⁺ 419.34 (calc'd 419.26).

TABLE 5 The compounds of Examples 56-59 were prepared according to the procedure of Example 55, using the appropriate starting materials. Calc'd Observed Example Mass Mass Number Structure Name M + H⁺ M + H⁺ 56

N-cyclohexyl-3-{2-[4- (difluoromethyl)piperidin- 1-yl]-1H- benzimidazol-1-yl}-N- ethylpropanamide 433.27 433.31 57

N-cyclohexyl-N-ethyl- 3-[2-(4- methylpiperidin-1-yl)- 1H-benzimidazol-1- yl]propanamide 397.30 397.40 58

3-[2-(4-tert- butylpiperidin-1-yl)- 1H-benzimidazol-1-yl]- N-cyclohexyl-N- ethylpropanamide 439.34 439.10 59

tert-butyl [(3S)-1-(1- {3- [cyclohexyl(ethyl)amino]- 3-oxopropyl}-1H- benzimidazol-2- yl)piperidin-3- yl]carbamate 498.34 498.32

Example 60 3-{2-[(4-tert-butylpiperidin-1-yl)methyl]-1H-benzimidazol-1-yl}-N-cyclohexyl-N-ethylpropanamide

Step 1: 2-((4-tert-butylpiperidin-1-yl)methyl)-1H-benzo[d]imidazole To a solution of 4-tert-butylpiperidine (48.3 mg, 0.34 mmol) and 1H-benzo[d]imidazole-2-carbaldehyde (50 mg, 0.34 mmol) in DMF (1.7 mL) at rt was added HOAc (39 uL, 0.34 mmol), followed by the addition of polymer-supported cyanoborohydride (137.0 mg, 0.34 mmol). After stirring overnight at 40° C., the reaction mixture was decanted away from the resin beads, filtered and purified via HPLC (10% to 60% CH₃CN in water w/0.05% TFA) to give the title compound. LC-MS m/z [M+H]⁺ 272.38 (calc'd 272.20).

Step 2: 3-{2-[(4-tert-butylpiperidin-1-yl)methyl]-1H-benzimidazol-1-yl}-N-cyclohexyl-N-ethylpropanamide To a solution of N-cyclohexyl-N-ethylacrylamide (24.0 mg, 0.13 mmol) and 2-((4-(tert-butyl)piperidin-1-yl)methyl)-1H-benzo[d]imidazole (30 mg, 0.11 mmol) in DMF (1.1 mL) at rt was added potassium carbonate (107 mg, 0.77 mmol). The reaction mixture was heated to 120° C. overnight, then filtered and dried. The resulting crude was purified by mass triggered HPLC purification (column: Waters Sunfire C18, 5u, 19×100 mm; solvent: gradient range: 10% to 70% final CH₃CN (0.1% formic acid) in water (0.1% formic acid) 50 mL/min, 8 min run time) to give the title compound. LC-MS: M+H 453.60 (calc'd 453.36).

TABLE 6 The compounds of Examples 61-62 were prepared according to the procedure of Example 60, using the appropriate starting materials. Calc'd Observed Example Mass Mass Number Structure Name M + H⁺ M + H⁺ 61

N-cyclohexyl-N-ethyl- 3-{2-[(4-ethylpiperidin- 1-yl)methyl]-5-methyl- 1H-benzimidazol-1- yl}propanamide 439.34 439.00 62

N-cyclohexyl-N-ethyl- 3-{2-[(4-ethylpiperidin- 1-yl)methyl]-1H- benzimidazol-1- yl}propanamide 425.33 425.50

Example 63 3-(2-cyclohexyl-1H-benzo[d]imidazol-1-yl)-1-(4-methylpiperidin-1-yl)propan-1-one

To a 2 dram vial was added 3-(2-cyclohexyl-1H-benzo[d]imidazol-1-yl) propanoic acid (15.0 mg, 0.055 mmol), 4-methylpiperidine (6.4 mg, 0.061 mmol), and DIPEA (14 μL, 0.080 mmol) in DMF (1.0 mL). The reaction was stirred at room temperature for 30 min, then HATU (23.0 mg, 0.061 mmol) was added. Then the reaction mixture was stirred at room temperature for 4 h. After filtration, reverse phase HPLC purification (10% to 70% CH₃CN (0.1% formic acid) in water (0.1% formic acid)) gave the title compound. LC-MS: M+H 354.18 (calc'd 354.25).

Example 64 N-cyclohexyl-3-(2-cyclohexyl-1H-indol-1-yl)-N-ethylpropanamide

Step 1: 3-(2-cyclohexyl-1H-indol-1-yl)propanoic acid To a solution of 2-cyclohexyl-1H-indole (50.0 mg, 0.25 mmol) in DMSO (1.2 mL) was added KOH (42.2 mg, 0.75 mmol), followed by methyl 3-bromopropanoate (58.7 mg, 0.35 mmol). The reaction mixture was stirred overnight at rt. The resulting crude was purified directly via Gilson HPLC (10-100% CH₃CN/water w/0.05% TFA) to give the title compound.

Step 2: N-cyclohexyl-3-(2-cyclohexyl-1H-indol-1-yl)-N-ethylpropanamide The title compound was prepared starting from 3-(2-cyclohexyl-1H-indol-1-yl)propanoic acid according to the procedure of Example 63. LC-MS: M+H 381.29 (calc'd 381.36).

Example of a Pharmaceutical Composition

As a specific embodiment of an oral pharmaceutical composition, a 100 mg potency tablet is composed of 100 mg of any one of the Examples, 268 mg microcrystalline cellulose, 20 mg of croscarmellose sodium, and 4 mg of magnesium stearate. The active, microcrystalline cellulose, and croscarmellose are blended first. The mixture is then lubricated by magnesium stearate and pressed into tablets.

Biological Assays TarO Biochemical Enzymatic Assay

Assay Background The pathway for the biosynthesis of wall teichoic acid (WTA) in Staphylococci involves a series of biochemical enzymatic reactions by proteins encoded by the tar genes (teichoic acid ribitol). The first enzymatic step in the synthesis of WTA is initiated by TarO, N-acetylglucosaminyl-1-P transferase, which catalyzes the transfer of N-acetyl-glucosamine-phosphate (GlcNAc-P) to an undecaprenyl phosphate (C55-P), also known as bactoprenyl phosphate, to generate C55-PP-GlcNAc (LIPID III). This assays measure the ability of a TarO inhibitor to specifically inhibit the formation of C55-PP-GlcNAc (LIPID III) product thereby blocking the synthesis of the WTA polymer.

TarO Biochemical Enzymatic Assay Protocol The TarO biochemical enzymatic assay is a liquid chromatography-mass spectroscopy (LC-MS) based end point assay that measures C55-P-P-GlcNAc (LIPID III) production. The TarO biochemical enzymatic assay was performed in a 384-well microtiter plate (Labcyte) with a reaction volume of 20 μl. The reaction mix contained 0.1 μgs/μl of TarO membrane preparation derived from MRSA COL (lysostaphin/lysozyme treated, centrifuged at 40K rpm, and re-suspended in 50 mM Tris pH 7.5, 10 mM MgCl₂), 1500 μM UDP-GlcNAc, ×75 μM C55-P substrates in 83 mM Tris pH 8.0, 6.7 mM MgCl₂, 6 mM CHAPS, and 8.3% DMSO buffer. The enzyme reactions were quenched by extraction in 40 μl of 1-pentanol containing 0.04 μM 15C C55-PP-GlcNAc, which was used as an internal standard. A 10 μl volume of the quenched reaction mixture (pH≈3) from each well was injected onto a reversed-phase column (C4, 5 μm, 2.1×50 mm, Thermo Scientific Biobacis-4) and eluted using a NH4Ac/H₂O/MeOH gradient (solvent A: 10 mM NH4Ac in water, pH 5.6; solvent B: NH4Ac (1 M)-Isopropanol (1:90, v/v, pH 5.6). The HPLC conditions were as follows: 15% solvent B for 15 seconds followed by a gradient to 90% solvent B in 90 seconds; then solvent B was kept at 95% for 10 seconds followed by a gradient to 8% solvent B in 0.1 minute. The column was then equilibrated at 15% B for 1 minute before the next injection. The flow rate was kept constant at 600 μl/minute. Mass spectrometric detection was carried out in the negative-ion mode using selected reaction monitoring (SRM). Typical mass spectrometric conditions were as follows: heated capillary temperature, 210° C.; spray voltage, 2500 V; desolvation gas (N2), 40 l/h; auxiliary gas (N2), 35 l/h. Selected ion current (SIC) chromatograms of C55-PP-GlcNAc and internal standard 15C C55-PP-GlcNAc were plotted and integrated using LCQuan incorporated in Xcalibur software (ThermoFinnigan). The linearity of C55-PP-GlcNAc concentration versus mass spectrometric signal (AC55-PP-GlcNAc/A15C-055-PP-GlcNAc) was determined with purified C55-PP-GlcNAc. The IC₅₀ values were calculated using the nonlinear regression analysis (sigmoidal dose response fit allowing for a variable slope) of percent inhibition data with minimum and maximum values set to 0 and 100 percent.

The compounds of the present invention, including the compounds in Examples 1-64, have IC50 values less than 100 micromolar (μM) in the TarO Biochemical Enzymatic Assay described above. Preferred compounds of the present invention have IC₅₀ values less than 100 nanomolar (nM) in the TarO Biochemical Enzymatic Assay described above. TarO Biochemical Enzymatic Assay IC50 values for specific compounds are listed in Table I.

TarO Inhibitor/β-Lactam Synergy Assay

Assay Background The TarO inhibitor/β-lactam synergy assay was performed to measure the re-sensitization of methicillin-resistant Staphylococci bacteria (MB5393: MRSA COL) to β-lactam antibiotics by TarO inhibitors. MRSA COL is a hospital-acquired penicillinase-negative clinically isolated strain commonly used in Staphylococcus aureus studies and is fully resistant to the antimicrobial bioactivity of β-lactam antibiotics, including but not limited to imipenem and dicloxacillin. The breakpoint concentrations (measure of susceptibility or resistance to a particular antibiotic) of β-lactam antibiotics have been established by the Clinical and Laboratory Standard Institute (CLSI); the clinical breakpoint for imipenem (IPM) is currently 4 μg/ml, and dicloxacillin (DCX) is currently 8 μg/ml. MRSA COL is fully refractory to β-lactam antibiotic effect at the current clinical breakpoint concentrations and as such MRSA COL is fully viable at these concentrations. When administered to treat MRSA as single therapeutic agents, the breakpoint concentrations of imipenem and dicloxacillin are significantly higher than the current clinical therapeutic threshold.

TarO Inhibitor/β-lactam Synergy Assay Protocol The β-lactam antibiotic concentration was fixed at the clinical breakpoint (imipenem 4 μg/ml or dicloxacillin 8 μg/ml) and the TarO inhibitors were titrated by 2 fold starting from the highest concentration of 200 μM with final DMSO concentration of 2% in the assay. 5×10⁵ colony forming unit of MRSA COL in cation-adjusted Mueller Hinton broth (CAMHB) was then mixed and the assay plate was incubated for 20 hours at 37° C. without shaking. After 20 hours, the optical density at 600 nm (OD600) was read for all wells to determine relative growth of MRSA COL. The MITC₉₅ concentration for imipenem alone was determined to be 32 μg/ml; the MITC₉₅ concentration of dicloxacillin alone was determined to be 128 μg/ml. The MITC₉₅ values determined for: 1) the TarO inhibitors alone; 2) the combination of a TarO inhibitor+4 μg/mL of imipenem (IPM); and 3) the combination of a TarO inhibitor+8 μg/mL of dicloxacillin (DCX) are shown in Table I.

The present invention shows that treatment of MRSA bacteria with a TarO inhibitor in combination with a β-lactam antibiotic (imipenem or dicloxacillin) reduces the concentration of β-lactam antibiotic required to render MRSA COL susceptible to β-lactam antibiotic treatment below the current clinical breakpoint concentration. When MRSA COL was treated with imipenem alone in the TarO inhibitor/β-lactam synergy assay described above, the inhibition of MRSA COL viability was not achieved until the imipenem concentration was greater than 32 μg/ml (8 fold higher than breakpoint). Further, when MRSA COL was treated with dicloxacillin alone in the TarO inhibitor/β-lactam synergy assay described above, the inhibition of MRSA COL viability was not achieved until the dicloxacillin concentration was greater than 128 μg/ml (16 fold higher than breakpoint). However, the TarO inhibitors tested in combination with the (3-lactam antibiotics imipenem and dicloxacillin showed a synergistic bactericidal effect resulting in the inhibition of MRSA COL at the current breakpoint values of imipenem (4 ug/mL) and dicloxacillin (8 ug/mL). As shown in Table I, the combination of a TarO inhibitor and imipenem showed a synergistic bactericidal effect when administered to treat MRSA COL because a concentration of 4 μg/mL of imipenem was sufficient to inhibit MRSA COL viability when administered in the combination with a TarO inhibitor, whereas as a concentration of 32 μg/mL of imipenem was required to inhibit MRSA COL when administered alone. Additionally, as shown in Table I, the combination of a TarO inhibitor and dicloxacillin also showed a synergistic bactericidal effect when administered to treat MRSA COL because a concentration of 8 μg/mL of dicloxacillin was required to inhibit MRSA COL viability in the combination whereas a concentration of 128 μg/mL of dicloxacillin required to inhibit MRSA COL when administered alone.

TABLE I Inhibition of TarO and Treatment of MRSA COL with a TarO Inhibitor, alone and in combina tion with Imipenem (IPM, concentration 4 μg/mL) or Dicloxacillin (DCX, concentration 8 μg/mL) MITC₉₅ (μM) MITC₉₅ (μM) MITC₉₅ (μM) Example TARO TarO inhibitor TarO inhibitor + TarO inhibitor + number inhibitor alone²; 4 μg/mL IPM³; 8 μg/mL DCX⁴; TarO IC₅₀ Bacteria: Bacteria: Bacteria: inhibitor (μM)¹ SA_MB5393 SA_MB5393 SA_MB5393 1 0.77 >200 1.82 6.25 2 0.66 >200 1.88 18.75 3 0.79 >200 4.17 20.83 4 0.84 >200 4.17 41.67 5 0.01 >200 0.01 0.02 6 0.02 >200 0.13 0.59 7 0.01 >200 0.20 0.20 8 0.03 >200 0.06 0.22 9 0.03 >200 0.13 0.79 10 0.04 >200 0.004 0.03 11 0.04 >200 0.40 1.04 12 0.06 >200 0.50 1.09 13 0.11 >200 0.35 2.19 14 0.12 >200 0.52 3.13 15 0.12 >200 0.52 4.17 16 0.15 >200 1.04 14.58 17 0.15 >200 0.98 6.25 18 0.29 >200 1.09 23.75 19 0.30 >200 1.95 28.13 20 0.36 100 1.56 12.50 21 0.40 >200 0.78 13.54 22 0.42 >200 0.36 0.88 23 1.09 >200 9.38 37.50 24 0.00 >200 0.04 0.46 25 0.05 >200 0.38 1.30 26 0.13 >200 1.30 4.17 27 7.32 >200 37.50 50 28 0.38 >200 1.30 4.17 29 0.52 >200 1.56 6.25 30 1.48 >200 18.75 25 31 1.77 >200 6.25 50 32 3.44 >200 20.83 20.83 33 0.06 >200 0.06 ND 34 0.04 >200 0.25 0.54 35 0.07 >200 1.95 9.38 36 0.13 >200 0.68 3.91 37 0.20 >200 1.69 12.50 38 0.24 >200 2.08 12.50 39 0.28 >200 4.69 12.50 40 1.35 >200 2.34 9.38 41 3.40 >200 5.47 37.50 42 3.77 >200 18.75 25.00 43 0.08 100 0.20 0.78 44 0.02 100 0.10 0.20 45 0.07 100 0.20 0.78 46 0.08 100 1.56 6.25 47 0.01 100 0.10 0.20 48 0.09 >200 1.56 50 49 0.11 100 0.78 6.25 50 0.14 100 0.20 1.56 51 0.15 100 0.39 3.13 52 0.23 100 1.56 6.25 53 0.26 100 1.56 6.25 54 0.45 100 1.56 12.50 55 0.22 >200 1.37 7.81 56 0.17 >200 1.17 4.69 57 0.21 >200 1.30 26 58 0.01 >200 0.02 0.13 59 7.99 >200 50 150 60 0.10 >200 0.78 6.25 61 1.05 50 6.25 25 62 0.21 >200 6.25 25 63 2.34 >200 18.75 ND 64 ND >200 6.20 ND ND is not determined. MITC₉₅ (minimum inhibitory threshold concentration) is the minimum concentration required to inhibit MRSA COL growth by 95%. ¹TarO IC₅₀ (50% inhibitory concentration) is a measure of biochemical inhibition of TarO enzymatic activity. ²The minimum concentrations of TarO inhibitors alone of >200 μM are designated as not having achieved 95% growth inhibition or having no growth inhibitory effect in the in vitro assay. ³The minimum concentrations of the TarO inhibitors of the present invention required to achieve MITC₉₅ when administered in combination with 4 μg/mL of imipenem (IPM). ⁴The minimum concentrations of the TarO inhibitors of the present invention required to achieve MITC₉₅ when administered in combination with 8 μg/mL of dicloxacillin (DCX) .

In Vivo Murine Systemic Infection Model

Background The murine systemic infection model determines the therapeutic efficacy of TarO inhibitor/β-lactam combinations in vivo. Staphylococci bacteria can cause a systemic infection and establish a robust growth in the kidneys of the infected animal. MRSA COL can establish an infection even in the presence of β-lactam antibiotic due MRSA COL resistance to β-lactam antibiotics. In this model, therapeutic efficacy is achieved when bacteria recovered from the TarO inhibitor/β-lactam antibiotic combination is greater than 100 fold lower than the vehicle alone control group.

Protocol Female Balb/C mice were rendered neutropenic (immune suppressed) with a single 250 mg/kg intraperitoneal (ip) dose of cyclophosphamide on Day 4. MRSA COL (MB 5393) was grown for 16 hours in trypticase soy broth (TSB) at 37° C. and 0.5 mL of diluted culture (˜1×10⁴ cfu) was administered intraperitoneal (IP). The TarO inhibitor and β-lactam antibiotic were administered alone or in combination by subcutaneous route at 2, 5 and 8 hr. post challenge (sc, tid). Twenty four hours post challenge mice were euthanized and the kidneys harvested, weighed, homogenized and plated to measure the total number of bacteria recovered as colony forming unit (CFU) remaining in compound treated groups as compared to vehicle (saline) or β-lactam antibiotic alone groups (statistical analyses was determined by one way ANOVA).

As shown in Table II, the TarO inhibitor of Example 37 alone reduced the number of bacteria recovered in colony forming units/gram of kidney to 1.5×10⁷ (1.3 fold lower), and the combination of TarO inhibitor of Example 37 and imipenem reduced the number of bacteria recovered in colony forming units/gram of kidney to 2.6×10⁴ (730 fold lower).

TABLE II Results of In Vivo Murine Systemic Infection Model Treatment Bacteria recovered Fold reduction vs. Groups [cfu/g kidney] vehicle alone Vehicle alone 1.9 × 10⁷ Not Applicable saline control Imipenem alone 1.0 × 10⁶ 19 (5 mg/kg) Example 37 alone 1.5 × 10⁷ 1.3 (100 mg/kg) Example 37 (100 2.6 × 10⁴ 730.8 mg/kg) + imipenem (5 mg/kg) *Data is an average of 5 mice for each treatment group

The scope of the claims should not be limited by the preferred embodiments set forth in the examples, but should be given the broadest interpretation consistent with the description as a whole.

While the invention has been described and illustrated with reference to certain particular embodiments thereof, those skilled in the art will appreciate that various adaptations, changes, modifications, substitutions, deletions, or additions of procedures and protocols may be made without departing from the scope of the invention. For example, effective dosages other than the particular dosages as set forth herein above may be applicable as a consequence of variations in responsiveness of the mammal being treated for any of the indications with the compounds of the invention indicated above. The specific pharmacological responses observed may vary according to and depending upon the particular active compounds selected or whether there are present pharmaceutical carriers, as well as the type of formulation and mode of administration employed, and such expected variations or differences in the results are contemplated in accordance with the objects and practices of the present invention. 

What is claimed is:
 1. A TarO inhibitor compound is selected from:

or a pharmaceutically acceptable salt thereof.
 2. A synergistic pharmaceutical combination, comprising: a TarO inhibitor compound according to claim 1; and a β-lactam antibiotic, where the β-lactam antibiotic is imipenem, dicloxacillin, cephalexin, or tebipenem.
 3. The synergistic pharmaceutical combination according to claim 2, further comprising a pharmaceutical carrier. 